... makes the following products: Hand-held rock drill, YN27 Internal combustion rock drill, Air leg-rock drill, tapered drill bits, ... bits, shank adapters and coupling sleeves, etc.1. FeaturesThe internal combustion rock drill type YN27J is a portable rock-drilling tool ... /YN27J Paving breaker/YN27J hand held rock drill/ YN27 Internal Combustion rock drill/ Gasoline hand hold jack hammer/Paving breaker ...