Magazines appear to be made with excellent materials and of quality manufacturing. Excellent fit and finish and springs were of sufficient length to indicate reliable feeding. In fact the springs were longer than those in Kimber factory magazines. The only issue I noticed was that the design/shape of the spring and follower is different than those in the factory magazine, when it comes time to replace them the Wolff springs recommended by Kimber will not fit. I guess I''ll have to cross that bridge when I get there. In the mean time, an excellent product.