I bought these for my KS-s18 EUC unicycle. It has air damped suspension and this allows me to add air pressure to the shock without needing the 'suspension block' that came with the bike. Using a suspension block when airing the suspension forces you to make the suspension partially compressed. This hampers accurate inflation because with the block in place and the spring compressed, you're inflating and metering with a reduced amount of air burst. Once the block is removed, the suspension is fully expanded and internal volume increases, significantly reducing air pressure. The only way to accurately fill the air shock and check the pressure is to fully decompress the shock. This "Universal Brass Valve Stem Extension" allows access to the air shock's Schrader valve even when the shock is fully extended, even without a block. Welcome to the improved suspension of your s18!