Fits: Most 12, 16 and 20 Ga and .410 pump shotgun barrels. Heatshields should not be used on Mossberg Mariner or Remington Marine Coat Shotguns. This will only fit if the barrel lug is more than 13.5 from the receiver. Does Not Fit Mossberg 590A Barrels.Note: Each Heatsheild should be custom fit. If you do not have the proper tools or do not feel comfortable fitting the heatshield to your firearm please enlist the services of your local gunsmith. ATI is not responsible for any damage caused by improper installation.Steel Formed Shotgun HeatshieldElongated Cooling Slots for Maximum Dissipation of HeatEasy Installation Simply Slide Over Barrel and Secure With Supplied HardwareAR-15 Style Fixed Nylon Ghost Ring Sights13-1/2 LongLimited Lifetime WarrantyMade in the USA