Groove Rite Clamp - What's it used for?

[sgs236]

Bought a box lot at a engine rebuild /repair shop auction this past weekend. This GROOVE RITE clamp was inside and I can't find much information on the internet about. Anyone know how or what you would use it for? Thanks in advance.

 

[Can I try?]

It appears to me that it's meant to be used in conjunction with a bench vise, as a means to securely hold a piston.