I finally broke down and bought one of these and spent money on other substitutes that were below average. Get it, you won't be disappointed. Drilled 7 holes in 1/2 marble tile. Towel rail (2), toilet paper holder and face towel ring are hung in less than 30 minutes. Remember to start at an angle and then work your way up to 90 degrees. He did not answer, it was even necessary to squirt water.