Type of Block?

by Lucy
(Washington D.C.)

This is kind of an odd question, but I thought maybe you could answer it. Someone gave me a pendant that he said was of something used in sailing. It's oval and has two holes in it, kind of like an 8 symbol. He said that it's used to connect two ropes that are coming from different directions, and to move these ropes quickly and easily around the boat. Does anyone have any idea what this is? Thank you!!