High Performance Signature Extended Invector Plus Choke TubesThe time has come for a set of true, high performance tubes to match the requirements created by the expanded line of Winchester shotguns. They set a standard as the finest Winchester choke tubes ever and offer performance competitive with the finest choke tubes on the marketFeatures: - 17-4 Stainless steel in natural finish- Extended design (3/4 beyond muzzle) with Winchester Signature Red band on front edge- Completely compatible with steel shot, lead short and heavy shot- Perfect concentricity for more uniform patterns- Knurled surface for easy insertion.- Invector Plus slots included for using a wrench- Precision internal and external dimensionsSpecifications: - Bore: .720- Constriction: .020