Band and housing of SAE Standard 300 Marine Grade Stainless Steel. Slotted 5/16" hex head screw is SAE Standard 305 Stainless. The extra high nickel alloy stainless steel meets extreme demands of corrosive and underwater environments. FEATURES: • Band and housing to SAE Standard 300 Stainless Steel • One piece stainless steel housing with interlocked construction • Combined screwdriver slot and hex head screw design allow use of screwdriver, socket or spintite.