Darn, I have seen these before. Two things come to mind,
Clamps for doing body work on cars, sheet metal work,
Or electrical related? Like the devices that hold big fuses in on overhead power lines?
Those are actually called hotline clamps. I am the purchasing agent for an electric co-op and buy a lot of them. The one on the left has a loop so it can be lifted into position with an extendo stick. Your smaller jumper wire is clamped into the smaller clamp and the larger then goes on your overhead conductor and is usually tightened with an extendo or hotline stick. It is similar to the grounding clamp shown in the earlier post, but smaller and for a different purpose. Fargo, as shown in the ebay post, is one of the manufacuturers of this type of equipment.
Both clamps are designed for use with a hotline, hot stick, extendo, shotgun pole etc. but they clamp onto the loop on the threaded end. The one with the extended lip is designed to make it easier to install on overhead lines. Use them all the time.