I needed a 4" hole saw to mount the signal light ring. In HD it would cost the same for a 4" as it did for this whole set. I figured even if I had a 4" siding slot I would still be ahead I cut 2 holes and had no problems Went through like clockwork and cut through the entire wall I had to clean the hole saw after each shift (pretty flat) but it didn't make much of a difference .Very happy with this purchase.