Blind Man's Chess Set , possibly by W. Howard

Antique chess sets for blind players are rarely found nowadays. Blind sets differ from other sets in several ways: the Black pieces typically have a knop or indicator, to differentiate them from white pieces; and the black squares are raised slightly over the white squares.

This set matches all characteristics of sets produced by William Howard of 62 Barbican, although I can't definitively say that W. Howard manufactured the set.