Most adaptable shoulder rest available.
If you fit one of the standard shoulder rests, good for you! There are cheaper options out there that are perfectly fine. But if you find your neck is too long, too short, or something is angled differently (collar bone, breasts, where you want to put your chin, etc), Bon Musica gives you the most control over the actual shape and attachment angles of any shoulder rest I have ever tried. You mold it to your physique. As such, it does not transfer to another person easily, so don’t bother offering it to a friend when they forget theirs. It also gives you the ability to try slight changes in angles that affect posture and thus sound production. If you are at the level where tiny changes in technique for things like fingered octaves or the precise contact point and angle for spiccato make a difference, I highly recommend giving this a try! Let gravity and your body be your friend rather than fighting against them…