Office Chair Category C

Office Chair Category C primarily refers to C-type office chairs that comply with the EN 1335-1 standard, as well as ergonomic chair C-series products represented by the Sihoo C300. The following provides an explanation from two dimensions: standard definition and typical products.

I. C-type Office Chairs in the EN 1335-1 Standard
According to the EN 1335-1 standard, office chairs are classified into three types: A, B, and C. The core functional requirements for C-type office chairs include adjustable seat height and reclining backrest. These two functions are the basic configurations of C-type chairs, aiming to meet users' needs for posture adjustment in different work scenarios. For example, seat height adjustment can accommodate office desks of different heights, preventing shoulder, neck, or waist strain caused by height mismatches; the reclining backrest function allows users to lean back and rest, alleviating fatigue from prolonged sitting.
In addition, C-type office chairs can be optionally equipped with other adjustment functions according to the items listed in Standard Table A1, such as armrest height/angle adjustment and headrest adjustment. These additional functions further enhance the chair's adaptability but are not mandatory. As a European general standard, EN 1335-1 also has clear regulations on the structural strength and material safety (such as formaldehyde emission) of C-type chairs, ensuring that the products comply with ergonomic and health and safety requirements.

II. Typical Representative of the Sihoo C-series Ergonomic Chairs
Taking the Sihoo C300 as an example, as a representative product of the ergonomic chair C-series, its functional design exceeds the basic requirements of the EN 1335-1 standard. For instance, the C300 second-generation series launched in September 2025 adopts the "Dynamic Tracking Support" design concept, achieving adaptive support for the lumbar and back regions through the SyncroFlex Lumbar-Back Gliding Technology. This technology can dynamically adjust the support force according to changes in the user's sitting posture, avoiding the problem of localized pressure concentration caused by the "fixed support" of traditional chairs.
In addition, the C300 second generation is also equipped with functions such as 4D adjustable armrests (up and down, front and back, left and right, rotation) and an intelligent gravity-sensing base (automatically adjusting the reclining resistance according to body weight), further optimizing comfort during prolonged sitting. These innovative designs have made it stand out on the best-selling lists of computer chairs on e-commerce platforms, becoming a popular choice in the high-end office chair market.

Summary: Category C office chairs include both general-purpose products that comply with the EN 1335-1 standard and functionally upgraded ergonomic chairs represented by the Sihoo C300. The former emphasizes the compliance of basic adjustment functions, while the latter enhances the user experience through technological innovation. Together, they form the market ecosystem of Category C office chairs.