There are many competitive fields and airsoft facilities in the US and Canada that have begun requiring biodegradable BBs. Elite Force offers a newly formulated airsoft BIO BB that breaks down within 180 days in a compost environment. Elite Force Biodegradable Airsoft Ammunition is available in .20 g, .25 g, .28g, and .32 g sealable bottles. This type of BB container allows you to store your BBs air tight, which tremendously increases the life of the BB. The Elite Force BIO Airsoft BB has been tested by veteran players for accuracy and consistency in multiple variations and models of airsoft guns including the SYSTEMA PTW Max and Super Max, proving the Elite Force BB as a perfected formula that accurately performs both during and after competition.