Check the listing for details. .17 HMR Muzzle Brake Compensator Ruger Precision Rimfire RPR .17 HMR 1/2-28 TPI. Color: Black, Condition: New. Listed at 29.99 USD. Length: 2.75" OALDiameter: .8995"Exit Hole: .253" Weight: 5oz Threads: 1/2-28Machined From Carbon Steel C1045 Heat TreatedBlack Nitride Finish For A Ruger Precision Rimfire Bolt Action RPR .17 HMR 17 HMR 17HMR 3 Large Baffles & 3 Ports For Maximum Compensation Includes 1 1/2" Appropriate Crush Washer Please Ensure Your Barrel Is Threaded 1/2-28 Before PurchasingLaser Engraved With Thread Pitch, Caliber, Model, Manufacturer Only One Brake Included, Two Shown For Picture Demonstration Purposes Only ShippingWe ship 5 days a week, Mon-Fri during business hours 9-5pm PST, and Saturdays we come in to ship orders out to prevent delays. We ship within 24 hrs if it is a business day.ReturnsWe offer a 30 day return policy. Buyer pays for the return shipping cost.Returns must be in 100% brand new unopened condition.We ship 5 days a week, Mon-Fri during business hours 9-5pm PST, and Saturdays we come in to ship orders out to prevent delays. We ship within 24 hrs if it is a business day.