I have used these bits for multiple port jobs on my Exhaust Manifold, Turbo, o2 housing, etc and they are still working great. Definite recommend!

So far the bits have worked great and have not failed or dulled.

I haven't used this burr set yet, but the tools look to be of good quality.

Better quality, more pieces, and half the price of NAPA.

agreat deal for the price, value&durability they retail else where sometimes for much more