Dave,
A pure graze fuze with a needle in the head and a detonator carried in an inertia pellet. The III* fuze is a conversion of the Mks II, II* and III to approximate to the last design (Mark IV) which had a 'feathered guard' to prevent the graze pellet working forward against the needle during flight (ie to stop prematures).
Nose fuze for RML 40-Pr and upwards, RBL 40-Pr in Land Service and 20-Pr in Sea Service.
Mark III* introduced 2 Dec 1892. All marks obsolete 21st July 1911.
[Refs: Notes (mine) and Hogg's. List of Changes]