Similar to a 'Berp' this visualizer is a horn mouthpiece with a cut-away cup so one can buzz quietly in a performance stance. Also this can be used to see your embouchure. Can be held in your hand, or inserted into your horn mouthpipe.
This non-mouthpiece helps to make every note focused and works well on both technical and lyrical passages, as well as warmups.
Just what the doctor ordered. You can buzz and make believe you're playing the horn and fingering if you want. Definitely improved my buzzing.