For installation the Sapim hexagonal nipple key is required
Most common material for nipples, brass nipples are generally nickel coated to ensure good corrosion resistance. Most wheel building robots can only work with brass nipples. Sapim offer brass nipples in silver and black.
Hexagonal head nipples allow to take higher torque without damaging the four spans of the nipple. Because truing is done from the head side that has a larger diameter. It can take more pressure. Hexagonal nipples are offered in 12, 14, and 16 mm.