These carbide blades are absolutely 100% quality, and cut like butter! I had a major issue though, and it follows: they did NOT fit on new my Ridgid oscillating tool, model number R2851VN - Series B. I had to drill a 13/64 hole on both sides of the blade for it to fit on my new Ridgid oscillating tool. I couldn't wait to see if they worked as advertised! The blades are extremely hard, durable, and strong! I just had to test a blade even though I had a definite issue with it fitting on my Ridgid oscillating tool. I put the following into a piece of 2X4: 3/8" steel bolt, 4" deck screw, 2" construction deck screw, 3" flat head nail, and a 2-1/2" square cut head masonry nail. The blade cut all of them with hardly any wear in under a minute. They would definitely last a long time, for they are SPECIFICALLY made for cutting hardened steel, and NOT for wood! I have NEVER used any blades for metal cutting like these in my life. Sadly, I contacted the company regarding my issue with them not fitting to no avail, and have to return them to Amazon. I wrote this review because they are absolute quality, and cut like butter, and would last a long time. I am very disappointed that the company would not assist me with my issue, for I don't know where I can buy quality blades likes these. I searched a long time to find such quality; but what good are they if I have to bore out each one of them to fit my Ridgid oscillating tool? I wanted to give them a positive review simply because of the quality of the blades even though I am not happy with their customer service. The company contacted me, and stated that they found out from the manufacturer that theses blades don't fit on my new Ridgid oscillating tool, model number R2851VN - Series B. They are kind enough to send me another set for free, and I will simply bore out each blade to make them fit. These blades are truly the strongest blades that I have ever used. Thank you seller for your assistance.