I am using this to open up cracks in concrete driveway for patching and resurfacing. Not bad. However it did not come with manual. Was searching web to see how to use a similar tool. Useful tips plus I found out I had to add oil. Nothing about adding oil came with product.
I was in the construction industry for 12 years, this has a metal casing and works as good as any I've ever used. Would be nice if they would recommend what oil to use, most people wouldn't know.