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 - $150

Violin 3/4 - $146

Violin 1/2 - $142

Violin 1/4 - $140

Viola 15", 15 1/2" or 16" - $154

Foam replacement all sizes -$27

Feet replacement all sizes -$28