This object is known as ‘Ariadne’s Clew-Box’ after its presumed use as a container for woollen thread. It is more likely that this is a bee-smoker, and the slots are for the smoke to come out to pacify beehives to enable the extraction of honey.
Bibliography
Evans, Arthur. 1928. The Palace of Minos at Knossos, II, pp. 308-309, fig. 179
Myres, John (ed.). 1936. British Archaeological Discoveries in Greece and Crete 1886-1936, p. 24