hi forest. SMC is very good about helping you if you call them. you can order direct from them as well. i got a rebuild kit for the ram that pushes my bay fridge/freezer in and out from them. that ram was an smc one.
it is a common valve and appears to be about 45 bucks. but there are many configurations.
http://www.smcpneumatics.com/search....=13&search.y=8
tom