The BLA drain plug kit is made from Nylon 6 which is durable and has a strong U.V. resistance. The plug also has good sealing qualities and a high quality Nitrile O-ring and it is also resistant to today’s fuels and oils. The drainage hole is 35mm and the cut out size of the base is 40mm. The 4 hole layout on the base matches several existing versions currently on the market which includes Quintrex, Stacer and Savage.