A glass thief is used to burgle a sample from your fermenter. Old school with no moving parts. Sanitize it, put into fermenter and allow the wine to fill. When you have the desired sample amount, plug the open with your finger and withdraw. The liquid stays as long as your finger is in place. When you let go of your end, it comes out the other end. Simple and easy.
Dimensions. Length: 11" (28cm), Diameter: 5/8" (1.6cm)