This is Dremel's 1/16" Quick Change Collet. 

FEATURES: A slim, aluminum tube for holding a bit. Provides the optimal grip for bits offered for the Dremel rotary tool line and Heavy-Duty Flex-Shaft Tool. Compatible with Flex-Shaft Tool handpieces #235 and #237. Collets feature small identification rings around their shanks, which correspond with the size of the collet. This collet has 3 rings.

INCLUDES: One Collet

REQUIRES: Dremel Rotary Tool

SPECS: Size: 1/16"

COMMENTS: This collet is not suitable for the #236 handpiece.