Fenix Picatinny Rail Tactical Flashlight Ring ALG-01 Specifications: With Plastic Spacer- Fits Flashlight Diameters 23.6mm-24.2mm (compatible with Fenix PD32) Without Plastic Spacer- Fits Flashlight Diameters 25.4-26.0mm (compatible with Fenix TK11, TK12, TH15, TK21, TA20, TA21) Material: Flashlight Ring- Aluminum, type 6063T5 Plastic Spacer- POM Hex Screw- Steel, type 22 Allen Wrench- Steel, type 45 Precision Machined Aluminum Anodized Black Matte Finish Mounting Base Designed with Locking Hex Screws to Fit on Picatinny/Weaver Rail.