Our BOLT Marker Clip is designed to securely hold markers and pencils. The clip is compatible with all Milwaukee head protection including helmets and hard hats. It easily clicks into the head protection's BOLT Accessory slots letting you use the universal accessory slots to clip in additional head protection accessories like ear muffs. The marker clip is part of Milwaukee BOLT System that lets you adapt to your jobsite by adding BOLT accessories to your Milwaukee head protection. All Milwaukee hard hats and helmets are BOLT compatible.