Yep, it was the M34 - looks a little like the M57 but puts out a lot more juice.
AKdeja- you can set claymores up for trip wire detonation also with a device that screws into the cap well and then attach a wire to it (might be what you were using), or you can improvise a tripwire detonation system pretty easily. Hell, you can even initiate one using a non-electric cap with a time fuse to keep trackers off your tail:)