air /petrol /electric rock drill from china type:YT24,YT28,YN30,YN30A,YN30E,YN27 ... ISO9001,CE super air /petrol /electric rock drill from chinaFeatures 1. The Internal Combustion Rock Drill is ... engine, an air compressor and a rock drill. 2. During operation, the rock powder is blown away ... , splitting and ramming by changing some components concerned.2. It has far-ranging applicability and can be used ...