These Greed Goods bung caps with ¾” knockout are extremely versatile and compatible with most US made 15g, 30g, and 55g drums. All caps are certified for use in UN certified drums to ensuring that you get the best quality product with no leakage. It can withstand high resistance to heat and severe weather conditions. Perfect for any emergency storage or transport, this bung cap offers long life as well as reduced labor and material costs!