The dmr sts simple tension seeker is designed for harder riding styles fit it for street dirt jumping and trials the stainless steel arm is tough and tucked out of harms way and the pu pulley runs on sealed bearings for durabilityit converts geared bikes to single speed and bolts into most vertical dropouts in minutes tensioning the chain is simple the sts is then securely clamped in place the sts is now available as a combo kit with the single speed spacer kit