The MILWAUKEE BOLT Marker Clip securely holds markers and pencils. The hard hat clip is compatible with all Milwaukee head protection, including helmets and hard hats. It easily clicks into the head protection's BOLT Accessory slots, freeing up the universal accessory slots to clip in additional head protection accessories like ear muffs. The marker clip is part of the Milwaukee BOLT System, allowing professionals to adapt to their jobsite by adding BOLT accessories to their Milwaukee head protection. All Milwaukee hard hats and helmets are BOLT compatible.