The Seaview Vault Series Drain Plug is engineered to screw right into the existing 1/2 NPT brass or stainless transom garboard. This plastic version is manufactured from glass fiber-reinforced ABS for better strength and flexibility. The durable construction increases fatigue endurance, resistance to high and low temperatures, and resistance to abrasion.• Triangular ergonomic cap• No tools required• NPT backup O-ring for a watertight fit• Approved for all marine environments including saltwater• It floats if accidentally dropped in the water• Fits all 1/2 NPT brass and stainless transom garboards Triangular ergonomic cap with no tools required NPT backup O-ring for a watertight fit Floats if accidentally dropped in the water | Vault Drain Plug