I used one of these to drill a big hole in the side of my PC chassis to improve airflow to the CPU. Worked really well. Most important advice is not to rush it. In one case I messed up the guide hole which took some effort to remedy. Tool does exactly what it's supposed to and the seller got it to my doorstep in about 3 weeks which is standard.
Very high quality! Will definitely buy again from this seller, fast shipment too! AAAAA+++++ Seller