Captain O-Ring - Rubber Oring Keyboard Switch Dampeners Blue [40A-R 0.4mm] Reduction (135 pcs w/ screen cloth) 0.4mm travel reduction for a softer landing and better shock absorption Significantly reduces keyboard sound level Minimizes finger fatigue by shortening travel and lessening impact High quality EPDM rubber resists cracking and tearing Includes 135 O-Rings & Captain O-Ring Screen Cleaning Microfiber Cloth