Fox suspension fox boost valve rp23 air canthe boost valve rp23 air can is a replacement air can upgrade compatible with the fox suspension float rp23 rear shock the boost valve technology offers a subtle improvement in mid stroke performance and an incredibly improved ramp up at the end of the stroke which helps prevent harsh bottom outs features compatibility fox suspension float rp23 rear shocks with eye to eye measurement of 216mm boost valve technologybuyfox suspension componentsfrom