Features: brand new and high quality Eliminating cavity sound, increasing sound thickness and reducing keyboard resonance. 3.5mm approatite thickness between the installation and the PCB and the steel plate, the steel plate and the PCB are used for clamping, no adhesive is required, and the light position is not affected. It fills the entire keyboard, the soud is thicker , the resonance of the plastic keyboard and the cavity sound are eliminated. This switch sound dampeners sheet, which is placed between the keyboard's circuit board (PCB) and the positioning board. It is a must for keyboard lovers to DIY your keyboard. These keyboard foam dampeners are made of soft foam sponge material, with high-efficiency noise reduction effect, and will not damage your PCB board. Specifications: Material: Foam Sponge Quantity: 2PCS Size : 6840: approx. 28x9.4cm/11.02x3.7in 8037: approx.28.5x9.4cm/11.22x3.7in AK: approx.28.4x9.4cm/11.18x3.7in (optional) Color: Black Thickness: 3.5mm Fit for: 61-layout Machenical Keyboard Package Includes: 2Pcs x Switch Sound Dampeners note: Please allow little errors due to manual measurement. Due to the difference between different monitors, the pictures may not reflect the actual color of the item.