2 3/8" caster for Wood, Tile and chair mats, add $21.75
2 3/8" caster makes for easier rolling on Carpet, add $14.50
1. Slide off from base underside center
2. Slide off old base and remove old column
3. Drop removed column into center hole of new base and slide back onto existing gas cylinder.
(A good time to replace Bearing Kit)
4. Replace clip with washer