Found this at an estate sale this morning, in a bucket of rain water, behind a barn, rusted solid. It cleaned up ok, but who or what is "RSUa160". And the forge mark looks familiar but I can't place it. Any ideas?

Derby brand, made in Poland from what I have dug up. RSUa160 I believe is the model no.

This is why I come here with my questions, someone always knows the answer! The collective knowledge of the folks here is staggering. These are indeed Derby pliers made in Poland, I would have NEVER thought to look outside the US to id them. Thanks again Bill.