Huian County Mubing E Commerce Co Ltd v. Interlink Products Intl Inc

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Huian County Mubing E-commerce Co., Ltd. (People's Republic of China)
  • Defendant: Interlink Products International, Inc. (New Jersey) and Eli Zhadanov (New York)
  • Plaintiff's Counsel: Glacier Law LLP
• Case Identification: 2:25-cv-02733, W.D. Wash., 03/16/2026
• Venue Allegations: Plaintiff alleges venue is proper in the Western District of Washington because Defendants directed patent enforcement activities into the district by initiating an Amazon Patent Evaluation Express ("APEX") proceeding against Plaintiff's product listings on Amazon's Washington-based platform.
• Core Dispute: Plaintiff seeks a declaratory judgment that its rain shower head product does not infringe Defendants' patents related to multi-function showerheads and that the patents are invalid.
• Technical Context: The dispute centers on the mechanical design of showerheads capable of directing water through different sets of nozzles to produce distinct spray patterns for both showering and cleaning.
• Key Procedural History: This declaratory judgment action arises from Defendants' pre-suit enforcement activities. Defendants accused Plaintiff of infringing the '435 Patent through Amazon's APEX process, threatening removal of Plaintiff's product listings. The complaint also notes that Defendants have asserted the '850 Patent against similar products in separate litigation in the Eastern District of New York.

Case Timeline

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 12,485,435 - "Showerhead Having Selector For Directing Water Flow In Independent Directions," Issued December 2, 2025

The Invention Explained

• Problem Addressed: The patent's background section notes that conventional showerheads are designed primarily for showering, and the resulting water pressure or spray pattern may be unsuitable for other tasks like cleaning tiled walls or tubs ʼ435 Patent, col. 1:19-27
• The Patented Solution: The invention is a showerhead with two distinct sets of nozzles. A primary set is located on the main faceplate for standard showering ʼ435 Patent, col. 4:2-4 A secondary set of nozzles is located on a different part of the showerhead, such as in a "cutout portion" on the side opposite the faceplate, and is configured to produce different spray patterns, like a fan-shaped spray or a high-pressure jet stream, suitable for cleaning ʼ435 Patent, col. 4:11-20 A user-operated "flow selector" allows water to be diverted between these different nozzle groups ʼ435 Patent, col. 4:32-40
• Technical Importance: The design aims to integrate distinct showering and high-pressure cleaning functionalities into a single, handheld showerhead, obviating the need for separate cleaning tools.

Key Claims at a Glance

• The complaint's non-infringement count focuses on independent claim 1 Compl. ¶28
• Essential elements of independent claim 1 include:
  • A head portion and a handle.
  • A plurality of first nozzles configured to direct water in a first direction.
  • At least one second nozzle configured to direct water in a second direction, transverse to the first.
  • At least one third nozzle adjacent to the second nozzle, also directing water in the third direction.
  • A "flow selector moveable between a first position" (directing water to the first nozzles), "a second position" (directing water to the second nozzle), and "a third position" (directing water to the third nozzle).
  • The second nozzle creates a first type of flow (e.g., fan-shaped spray) and the third nozzle creates a different, second type of flow (e.g., jet stream).
• The complaint does not explicitly reserve the right to assert dependent claims but seeks a declaration of non-infringement of "any claim" Compl. ¶27

U.S. Patent No. 11,992,850 - "Showerhead Having Selector For Directing Water Flow In Independent Directions," Issued May 28, 2024

The Invention Explained

• Problem Addressed: As the parent patent to the '435 Patent, the '850 Patent addresses the same technical problem: the inadequacy of conventional showerheads for cleaning tasks due to their spray patterns and pressure levels ʼ850 Patent, col. 1:10-21
• The Patented Solution: The solution is a multi-mode showerhead that uses a system of internal plenums (chambers) to manage water distribution. A handle delivers water to a "flow director," which can be moved by a selector switch ʼ850 Patent, col. 3:32-38 Depending on the selector's position, the flow director connects the incoming water channel to one of three separate plenums. Each plenum, in turn, feeds a different set of nozzles, such as the main faceplate nozzles, a fan-spray nozzle, or a jet-stream nozzle, allowing the user to select the desired function ʼ850 Patent, col. 3:56-62 '850 Patent, Fig. 2C
• Technical Importance: This patent details a specific internal architecture using distinct plenums as the mechanism for routing water to achieve the multi-functionality described in the patent family.

Key Claims at a Glance

• The complaint targets independent claims 1, 9, and 14 Compl. ¶51
• Essential elements of independent claim 1 include:
  • A head portion and a handle with a first channel.
  • A faceplate with a plurality of first nozzles.
  • A second nozzle and a third nozzle separate from the faceplate.
  • A "first plenum" fluidly coupled to the first nozzles.
  • A "second plenum" fluidly coupled to the second nozzle.
  • A "third plenum" fluidly coupled to the third nozzle.
  • A "flow director" moveable between positions to fluidly couple the handle's channel to either the first, second, or third plenum.
• The complaint seeks a declaration of non-infringement of "any claim" of the '850 Patent Compl. ¶50

III. The Accused Instrumentality

Product Identification

• The Accused Product is Plaintiff's "rain shower head" sold on Amazon.com Compl. ¶10 Compl. ¶24

Functionality and Market Context

• The complaint describes the Accused Product as employing a "materially different flow-selection structure" from that claimed in the patents Compl. ¶28
• Its mechanism is characterized as a "rotatable disc/faceplate mechanism" that operates in "multiple discrete positions" to route water through different internal passageways Compl. ¶28
• A key feature alleged to distinguish the Accused Product is an additional "off" position where no water is discharged, a configuration the complaint states is not recited in the asserted claims Compl. ¶28
• The complaint asserts that the Amazon marketplace is Plaintiff's primary sales channel in the United States, positioning the Accused Product as a key part of its business Compl. ¶15

IV. Analysis of Infringement Allegations

No probative visual evidence provided in complaint.

The complaint seeks a declaratory judgment of non-infringement. The following tables summarize the Plaintiff's arguments for why its product does not meet the patent claims.

'435 Patent Infringement Allegations

'850 Patent Infringement Allegations

Identified Points of Contention

• Scope Questions: A central question for the '435 Patent will be whether the claim language "moveable between a first position... a second position... and a third position" reads on a selector that may also have additional positions, such as the "off" position in the Accused Product Compl. ¶28 For the '850 Patent, the dispute will turn on the definition of "plenum" and whether any internal water-routing chamber in the Accused Product falls within that definition.
• Technical Questions: The case raises the factual question of whether the Accused Product's "rotatable disc/faceplate mechanism" is structurally and functionally equivalent to the claimed "flow selector," which the patent figures depict as a sliding switch '435 Patent, Fig. 2A For the '850 Patent, the primary technical question is whether the Accused Product contains any internal structures that function as the three distinct, claimed "plenums" Compl. ¶51

V. Key Claim Terms for Construction

The Term: "plenum" ('850 Patent, Claim 1)

• Context and Importance: The Plaintiff's non-infringement argument for the '850 Patent hinges entirely on the assertion that its product "has no plenum" Compl. ¶51 The definition of this term is therefore dispositive for the '850 Patent infringement analysis.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The term "plenum" is not explicitly defined in the specification. A party could argue for its plain and ordinary meaning, which might encompass any enclosed chamber that contains pressurized fluid (water) before it is distributed to the nozzles.
  • Evidence for a Narrower Interpretation: The specification consistently refers to three distinct plenums: a "first plenum 212a," a "second plenum 212b," and a "third plenum 212c" '850 Patent, col. 3:56-58 Figure 2C depicts these as physically separate chambers within the showerhead's flow distribution architecture. A party could argue that the term requires the specific multi-chambered structural arrangement disclosed in the preferred embodiments.

The Term: "flow selector moveable between a first position... a second position, and a third position" ('435 Patent, Claim 1)

• Context and Importance: The Plaintiff argues its "rotatable disc/faceplate mechanism" with an added "off" position is a "materially different" structure Compl. ¶28 The case may turn on whether this accused mechanism meets the "moveable between" limitation.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The claim language uses the open-ended transition "comprising." A party might argue that the presence of additional positions (like "off") does not preclude the selector from being "moveable between" the three required functional positions.
  • Evidence for a Narrower Interpretation: The patent figures depict the "flow selector 116" as a switch that moves within a defined slot to discrete positions corresponding to the three claimed functions ('435 Patent, Fig. 2A; '435 Patent, col. 4:32-40). A party could argue this disclosure limits the claim scope to a selector with only those three operative positions, excluding selectors with fundamentally different structures or additional settings like a rotatable disc with an "off" state.

VI. Other Allegations

Indirect Infringement

• This is a declaratory judgment action where the Plaintiff denies liability. The complaint asserts that the Plaintiff does not induce infringement because it has not encouraged or intended for customers to practice every claim limitation Compl. ¶30 Compl. ¶52 It further denies contributory infringement, arguing the Accused Product is a "staple article of commerce suitable for substantial non-infringing uses" Compl. ¶30 Compl. ¶52

VII. Analyst's Conclusion: Key Questions for the Case

This case appears to center on fundamental, potentially dispositive, disputes over claim scope and factual correspondence. The key questions for the court will likely be:

• A core issue will be one of definitional scope: does the term "plenum," as used in the '850 Patent, require the specific three-chambered architecture shown in the patent's figures, or can it be construed more broadly to read on other forms of internal water-routing channels? The Plaintiff's stark assertion that its product "has no plenum" puts this question at the forefront.
• A second key issue will be one of structural and functional correspondence: does the Accused Product's "rotatable disc" selector, which includes an "off" position, fall within the scope of the '435 Patent's claim to a "flow selector moveable between" three specific functional positions, or does its different mechanical operation and additional setting place it outside the claim?