Application These cylinders are used in cylindrical locksets, deadbolts and Ket in knob. Mul-T-Lock provides an extensive product range to fit a wide variety of popular brands. Operation Rotation with operating key. Materials Body and plug: high-quality brass Tail pieces: steel Pins: nickel silver and stainless steel Standard finishes Nickel chrome matte; Shiny brass Special finishes Nickel chrome; Antique bronze; Antique brass Cylinder mechanism Mul-T-Lock's unique, high-precision pin tumbler system.