Dmr simple tension seeker single speed kitif youve got vertical dropouts grab the simple tension seeker and spacer kit combo pack and convert your bike in one hit used to keep the chain tensioned on your single speed set up cartridge bearings in the roller keeping it working smoothly bolts into your vertical drop out and has a sizeable amount of adjustment to set it up the way you want features the single speed conversion kit is the most effective and easiest way of converting you bike to