The Valken Accelerate ProMatch 0.28g biodegradable BBs are manufactured in Taiwan by one of the best known BB manufacturers. These 6mm BBs are precision grade quality, completely spherical, contain less than 5% air bubbles, and polished multiple times throughout the production process to ensure that the BB is seamless and has no surface imperfections. These 6mm precision BBs give you greater accuracy and consistency, and they are packaged in a unique rectangular bottle with a screw-on cap making storage, transport, and loading simple and convenient. Our BIO BBs are made from PLA (Polyactic Acid), which is recyclable and compostable thermoplastic derived from a renewable, earth friendly resource, such as corn starch. Accelerate BB bottles do not roll around like other round bottles, which can spill easily. We recommend our Valken M4 Magazine Style BB Speed Loader for use with Accelerate BBs when loading mid-cap magazines.