Needless to say, a shock pump is an essential item if your bike has an air-sprung shock, but this little number from Topeak has a trick hidden up its screw-on sleeve. If your shock fails out on the trail, you can screw the pump down as a rigid replacement to get you home.
As a shock, it works fine. It's a bit more fiddly than a full length Fox unit, but more than adequate for the job. It pumps up to 300psi and has a 360- degree rotating hose and a pressure-release button. The principle is great. We can't remember the last time an air shock or fork failed on us, but it's best to go prepared.