B.E.R.P. Embouchure Builder for Trumpet

This is a great tool. As BBtrumpet says in one of his videos, if you have only 15 minutes a day for practising the BERP is the tool for keeping your sound and endurance at least at some acceptable level.
For very heavy or special mouthpice receiver designs it might not be possible to mount it on your trumpet.
For any standard receivers (like Bach etc.) you will be able to mount it and use it.
There is a big difference between lipp or mouthpice buzzing and using a BERP!

Where lip and mouthpiece buzzing might even have negative impact to sound and embouchure, I coul not perceive anything negative when using the BERP. Even if practising a whole weak (10-15 minutes a day) exclusively with the BERP.

If doing it right you will improve your toung and pitch control drastically.

It does what it claims. Although the quality of the finishing a bit inferior with sharp edges here and there. When you're paying 15 Euro for a piece of plastic, you expect it to have a better finishing. Apart from that it didn't fit properly in the lead pipe so I had to use extra filler material for a tight fit. Although it says in the manual you might have to use pvc tape for a better fit, nevertheless the whole process is annoying. For trumpet, I found that back pressure equals to the instrument when the dial is pushed to the lowest position leaving all the hole open, not while 'parked' covering the bottom perforations as it says in the manual.