it is a fairly modern tatting shuttle. used to make lace, doilies or whatever else you would knit or crochet. it one uses it to make series of tiny knots all joined together. i have found some at estate auction/sales from the fifties that are of that old plastic that many household emplements were made of after WWII. if you look online, you can find many tatted examples. and even tutorials. an old needle work style that is becoming popular again.