This O-ring kit from PDI is designed to replace both O rings in all styles of PDI pistons for the APS2, L96, or M24 spring airsoft sniper rifles.
The large oring from the PDI sniper rifle o-ring kit fits the outside of the piston in any APS2 type airsoft rifle and provides the air seal. The smaller o-ring is glued to the front of a PDI piston and provides cushioning.
To install the small o-ring, remove all oil and grease and use super glue to affix in place. Take care to not let any super glue touch the large o-ring.