Ohlins TTX1 Air Shock - Dual Open-Eye Mount - 210x55mm (Metric) YGroup_7033706151981 It features updated internals to

It features updated internals to be more reliable than ever and provides effortless actuation with less force required to drop it

and the dimension is for the diameter of the tube

Cons: Maybe you need a 31

5mm and 3mm made from hardened and tempered industrial tool steel

Fits 28-40 mm internal rim widths depending on model selected

Ohlins TTX1 Air Shock - Dual Open-Eye Mount - 210x55mm (Metric) YGroup_7033706151981 It features updated internals toA high performance, robust air sprung shock; the TTX1Air offers the same performance as the TTX2Air but in a more compact single can package; for bikes with a more linear shock curve with less need for bigger air volume and a lower level of progressivity. The TTX1Air also features a new slimmer fit end eye design to fit more frame designs. The TTX1Airs compact design weighs 60 grams less than the TTX2Air for a 210x55mm shock. A specific wiper seal and