Be careful....my neighbor was useing one to open drain tile in his vineyard and injected water into his hand from the high pressure jet head......he was pulling the hose out of the pipe and didnt think he was close to the end where the jet was attached......the lesson learned is to mark the flex hose about 10 feet from the jet end......when you get to that mark turn off pump then pull the rest out......also feed into pipe before turning on pump so it doesnt fly all over and hit you......ware heavy gloves and eye protection.....the jet head has rear faceing jets that propel it forward along with front jets that blast the clog.....you have to work the hose back and forth as the jet head pulls itself into the pipe and eats through the clog.....they work pretty good......just be careful......Len