This item is a set of optional parts for detailing ship models. It requires both cement and painting to complete or use.
A box full of IJN equipment, such as machine guns and "optical weapons" (I think Hasegawa is referring to the ranging and sighting equipment with that phrase...). Set A includes 35 different types of items, as illustrated below, to improve your 1/350 IJN ships. Injection-molded plastic and photo-etched metal parts.