... ,YT28,YN30,YN30A,YN30E,YN27,YN27C,YN27T certificate:ISO9001,CE super air /petrol /electric rock drill from chinaFeatures 1. The Internal ... rock-drilling tool, composed of a small petrol engine, an air compressor and a rock drill. 2. During operation, the rock ... on high mountains, and places with no power supply and air compressing equipment, and especially suits the temporary projects that the ...