I'll voice a similar opinion. I have used them several times now and have been very happy, especially with the "practice kit" which comes with every order. I very often either have a lesser (backup) body of the same type, or I buy one to use the practice kit on! So far the practice kit and the non-practice have gone on perfectly. Never had a mixup. I now own the most hideous Contax 137 EVER in neon pink snakeskin covering.