We are on a slab and we had a clog in our kitchen and laundry room drains. When plunging, I began to get sand in the sink which indicated that we might have a break in the line. It took multiple calls to plumbers and a couple of plumber visits before I called Happi. They had the right technician, Enrico and they had the needed small camera to scope the line. Good news. No break. Just egg shells. Prompt, friendly and got the job done!