Bulk Sapim nipples in a variety of styles - see type column for part specificationsStandard Polyax - The round shape of the head of the polyax nipples work like a ball-joint between the rim and the nipple ensuring a better spoke/nipple lineSecure Lock - Locking mechanism that prevents nipples from untightening during wheel truing, machine compatibleDouble Square - Allows the use of internal or external spoke wrenches - wrench flats above and below the rim interface rather than standard slotted spoke nipplesHex Square - Hexagonal head allows truing from the head side for hard to service spokes, and can resist higher torque without damage to the flatsStandard Polyax2.0x16mmIndividualBrassBlack