Slightly bizarre, it goes in the water with the eggs & is suspended on the rim of the saucepan by a hook & chain and when the wax turns transparent the eggs are ready. Looks c1950s, when researching it an exact same item was found & was made by a Japanese Co named ASANO. Selling as UNTESTED and as is.
Measures 85mm x 122mm x 7mm thick when closed. Unsure of use, size suggests too thin to be a cigarette case. Externally very nice with only minor wear, internally heavily toned with spot marks...