... China for many years. Including of tapered button bit, retract button bit, thread button bit. With ISO certificate & quality control. Button bits ... can manufacture the following types: A. Taper button bitTapered button bit(28mm, 30mm, 32mm, 33mm, 34mm, 36mm, 38mm, 40mm, ... .productShow(); oProductShow.init( { 'aImgSrc': aBigImageSrc } ); } )(); Button bits for Rock drilling 34mm/ 38mm/ 40mm/ 43mm etc