The Black Arts Design AEA HP Series AR Style Grip Adapter allows shooters the flexibility to install an AR Style grip of their preference. After all, grips are like pens, everyone has their favorite. The grip adapter installs with one M6 screw and keys into the HP's trigger guard for a rock-solid attachment point for your selected grip. Requires use of the industry standard 1/4x28 screw for AR-style grip attachment. *** Rigid beaver tail grips are not compatible. However, flexible beaver tail grips such as the Ergo Air grips can be used with the grip adapter*** ***Optional: Grip Installation Hardware Kit 1/4-28 x 1 Slotted Pan Head Machine Screw and Star Lock Washer. Material: CNC machined 6061-T6 aluminum with a Type II anodized finish. Features: Simple and quick install. Designed to key into the trigger guard for a solid and secure attachment point.