It is an Anti-Zep design by Vickers. The sub-munitions are filled with incendiary composition. Eject function is like a time fuzed Shrapnel. Dates from 1916.
Dave,
It is a British 'baby bomblet'. Came in two sizes, 5 oz or 6.5 oz. Incendiary and a chemical version was designed. I will find some chapter and verse.