Constructed of steel, they are electro plated to withstand the toughest corrosive environments. The base of the magazines is encased in a high tech polymer sleeve. A hi-tensile compression spring provides reliable feeding and long life. Technical Specifications Weight 0.3lbs Color Black Compatible with Beretta 92F/S Caliber 9x19mm Capacity 30 rounds Body Material Steel Spring Material Music Wire Finish Cation Electrodeposition Coating