Second square D. Make sure it will handle the current draw for your machine and that it has the right cut in/ cut out range. Most air nailers and staplers work at 100psi or less depending on fastener length, so you want a cut in pressure at about that psi and 125 to 135 is more than adequate for woodworking needs. You don't want to run at pressures higher than you need because it just wears it out faster for no useful reason.
Someone I consider a master woodworker once told me that a master woodworker is not someone who never makes mistakes. He is someone who is able to cover them up so that no one can tell.