Tool ID help

[jgarrett]

I am guessing some sort of hold down fixture similar to 1-2-3 blocks but would like to know for sure.
They are about 6" long.
Thanks,
Julian

 

[Mike N]

Looks like some homemade milling vice parallels.

Probably just some mild steel with lightening holes.

 

[jgarrett]

Don't think so...the half holes are threaded.