I had seen the Larry Meregillano Compression Training System on a few trumpet player posts and bought one not knowing if it would help improve my stamina and range. Not only did these get better my sound has also improved over the full range. If I don't have time to practice spending time with the CTS helps keep the chops in good order. Soul band gigs are easier as is teaching for hours. Well worth purchasing and with first class service from Thomann you can get going in a few days from buying. Go for it.... it really does work