Other chain tensioners often attach to the axle and to the derailleur hole. If you have a thick non-turn washer on the axle, this doesn't work. So this tensioner attaches like a rear derailleur, to the rear derailleur hole only. It is pre-aligned so cannot the jockey wheel cage cannot be moved in or out for unusual applications. The spring on this tensioner is more powerful than most derailleur tension springs.
The tension wheels on the CT-S500 chain tensioner do NOT have side to side adjustability. We therefore recommend it for multi-speed hub use rather than single-speed conversion use. It can be used with single-speed conversions however, provided that you adjust the side-to-side position of the rear sprocket to suit the position of the tensioner wheels.
The CT-S500 chain tensioner is supplied with a set of three washers of different thicknesses to allow for small side-to-side adjustments of the unit, to compensate for different thicknesses of derailleur hanger.