... drill from china type:YT24,YT28,YN30,YN30A,YN30E,YN27,YN27C,YN27T certificate:ISO9001,CE super air /petrol ... tool, composed of a small petrol engine, an air compressor and a rock drill. 2. During operation ... rock powder is blown away by the compressed air produced by the machine itself. 3. It ... mountains, and places with no power supply and air compressing equipment, and especially suits the temporary ...