This post is long overdue. It's rare in this day and age to come across business people who care about the customer and stand behind their products. I recently had a great experience with glass holes. Over the summer I drilled my 75 and was very nervous. I ordered the diamond bit and overflow box from them and was more than happy. They had great instructions and made a stressful situation much easier. Their approach was humorous and productive. I succeeded and enjoy my overflow greatly! Hats off to glass holes!