This core drill worked great for my application installing a mini AC split system. I had to drill through some walls that were concrete and plaster over the adobe walls. I also had to drill through sandstone and that worked great there too. This ensures clean entry and exit despite the hard but brittle materials. The only caveat I have is that when I rented a drill from my local rental store, Home Depot, I needed an adapter in my case. Since Home Depot didn't provide this, I had to purchase itβ¦