Ningbo chengyi balls co.,ltd has been professional manufacturer of airsoft BB Bullets for many years from 2000.Our Airsoft BB bullets brand is CYC,it contains 0.12g ,0.25g,0.28g ,0.30g ,0.32g 0.36 0.40 ,and bio 0.2g  bio 0.23  bio0.25  bio 0.28 bio 0.30  bio 0.32  bio 0.36 All BB bullets diameter is 5.95+/-0.01mm. And no air bubble inside of BBs.  By the way,we also make OEM for our customers if our customers want their own brand...