For use in Spring, Gas and Electric airsoft guns. 6mm biodegradable airsoft BBs Highly polished 0.20 grams 2700 rounds White 100% eco-friendly, biodegradable resin 5.930mm +/- 0.025mm dia., 5.928mm mean dia. 5.907mm min. dia., 5.947mm max. dia. Takes approx. 11 months to degrade when exposed to the elements (rain, snow, etc.) For precision airsoft use Made to exacting standards using high-quality materials. Bio-resin research conducted by our research lab in Holland, and manufactured on the most advanced equipment in our plant in Seoul, South Korea.