Used as part of the Dowel Pin Puller to remove stubborn dowel pins from blocks, heads, flywheels and more. The tightening sleeve is used to lock the collet to the dowel pin you are pulling. Always install the tightening sleeve with the flared end toward the collet. This will allow the sleeve to slide over the collet. Also, be sure to select the right collet for the dowel pin you are pulling.