There are no replacements for the Jekyll's air shock that I'm aware of, only stuff that came stock on the bike. If you've got a 2003 or newer Cannondale offered a couple different types of shocks but it's impossible to find them anywhere but used on Ebay. You can also send the shock you've got now back to Push and have it revalved so it basically becomes a top of the line shock again. That's what I did.