Universal Fit Design: Block-style spark plug wire dividers with universal mounting tabs for clean, organized wire routing on a wide range of applications 8mm Wire Compatibility: Designed to work best with 8mm spark plug wires while also fitting smaller wire sizes Secure Wire Retention: Recessed Allen bolt design helps firmly hold wires in place to prevent movement and cross-contact Easy Installation: Includes Allen wrench for quick and straightforward installation without the need for special tools Clean Engine Appearance: Keeps spark plug wires neatly separated for an organized, professional-looking engine bay setup Universal mounting tabs. New, block style wire retainers fit 8mm & smaller wire sizes and are secured with recessed allen bolt. (Allen wrench included). They work best with 8mm wires.