What is it???

Great day at the thrift store.  Found some very good things at very good prices!  And then there's this:

Does anyone know what it is?  The little black things are flexible and rubbery.  One of my favorite things about thrift stores is the odd things that we just really don't know what they are... It's fun to guess and try to imagine what anyone could do with some of these things.  So, any guesses?  We couldn't figure this one out at all!   --Oh, and I didn't bring it home with me, just in case anyone wondered.  Someone let me know if it is a highly useful thing that I can't live without, okay?