The ATI Deluxe V-Block heatshield is the industry"s first ever "free floating" heatshield. The rear of the heatshield is secured to the rear of the barrel with a Dupont Extreme Temperature polymer clip while the front of the heatshield is suspended above the shotgun barrel by two Dupont Extreme Temperature polymer V blocks. Both the rear clip and front V blocks include an underlying high temp resistant silicon pad that can withstand temperatures in excess of 600 degrees. The industry"s first ever free float style design to prevent any metal to metal contact between the heatshield and shotgun barrel. Constructed of high strength steel With Matte black powder coating. Dupont extreme temperature polymer clip and V blocks secure the heatshield to the shotgun preventing sliding and Movement of the heatshield. High temperature resistant silicon pads protect the shotgun barrel finish. Includes aluminum CNC Machined ATI dovetail picatinny rail attachment (rail not included). Fits with or without a mag extension. Fits 12 gauge Mossberg 500 & 590. Halo heatshield length is 16 1/4" or 16 1/2" with the optional 2" picatinny rail installed. Halo heatshield may not fit 18" barrels with a Muzzle standoff.