The F/C key and the E/B key from a defunct Boosey & Hawkes Edgware clarinet. Sterling silver earwire. Brass decorative elements. The clarinet keys are nickel plated, but should not be a problem for allergies as they will not touch the skin while hanging.
Boosey & Hawkes was a clarinet making firm in London, UK up until the 1980s. The Edgware clarinet was a student clarinet (and a very poor one at that, in my humble opinion). The name Edgware comes from the name of the road the factory was located on. Boosey & Hawkes was also a publisher of classical sheet music. Fun fact: my dad tried to learn to play clarinet on a Boosey & Hawkes clarinet. This is not that clarinet.