I'm very disappointed with the Jazzlab pro XL. The "doesn't slip" part is not true as within minutes of playing, the extendable lower part is sliding all over my chest right and left, rarely staying centered, and in consequence, raising the right or left shoulder pads. In winter a coat will keep then down on your shoulders, but doesn’t stop the slipping all over your chest. On top of that, the system for the telescopic adjustable front extension doesn't stay screwed tight letting the extendable part slowly slide out, even falling to the ground while playing a couple of times. It’s even worse if you try to use it sitting down. The idea was great but does not translate into practice. Maybe it’s good with altos or tenors, but definitely uncomfortable with a baritone.