Overland Hadley
on a journey
By the way I picked up one of those jacks at my local harbor freight to check out. When fully extended its 52" from bottom plate to the very top of the main body tube. So it might not be too useful for a normal slide in the bed truck camper (since the jacks usually bolt onto the camper higher than that) without either rigging up a drop bracket or using a longer extension tube (I'd shoot for a longer extension tube personally). Pretty basic design but it seems like it'd work fine for the occasional on/off. However it only has ~14" of travel so if you'd want to really lower the camper down you'd need to block it and then readjust the screw/drop let position before lowering farther which could get annoying. However considering you can get a set of 4 for the price of 1 actual camper jack it just depends on where your priorities are.
Thanks for the additional information.