Standard double action cushions rated 88A (medium) used on Sunlite plates and other Suregrip plates.
 
These are sold as a pack of 4 and are all barrel shaped cushions.
One roller skate requires 4 cushions, so you will need 2 packs to change cushions on both skates.
 
These cushions will fit most basic plates.  If you have a higher end plate, eg. Avanti, Reactor, Pilot - you will need a shaped cushion to fit.
 
Cushions are fun to experiement with as they really change up the ride and responsiveness of your skates, very cheaply!
We suggest you do some testing of your own to find out what combination you like for the type of skating you do.
 
Technical Specifications:
Outside diameter 25mm
Inside diameter 9.7mm
Height 14.25mm