6mm plastic airsoft BBs Biodegradable 0.25g 4,000 rds White Bioval Technologies biodegradable airsoft BBs are currently the only biodegradable BB approved for use by the U.S. Department of Natural Resources, Washington. These high-quality BBs are used by military & law enforcement personnel during training and are ideal for intense airsoft skirmishes! The BBs come in a resealable bag for easy carrying in the battlefield.