Bon Musica 

This multi-adjustable shoulder rest can be an excellent fit for those requiring stability

It quite literally hooks over the shoulder. The breast part and hooked section can both be bent by hand to adapt to your shoulder specifically

Sizes:

Violin 4/4 - $136

Violin 3/4 - $132

Violin 1/2 - $129

Violin 1/4 - $127

Viola 15", 15 1/2" or 16" - $140

Foam replacement all sizes -$24

Feet replacement all sizes -$25