This barrel goes perfectly with my BC Tosca and fixes the intonation problems that I had with the original barrels. It's easy and fast to adjust the length - you don't even have to stop playing if one hand is free:) Although If I were to buy it again I would choose the 63mm one because I rarely use it scrolled more than to a level 3, but sometimes I need it to be even shorter when the clarinet is cold! For me, it also changes the sound a bit making it warm and beautiful!