Why does the kitchen bat set include an extra stainless steel lid in addition to the three storage lids?

SHIMOMURA's kitchen bat set includes 3 stainless steel bats, 3 mesh strainers, 3 polyethylene lids, and 1 stainless steel lid^[1]. There are three translucent lids that fit each bat, but only one stainless steel lid. The material for the bats, mesh strainers, and stainless steel lid is all 18-8 stainless steel^[2], and the translucent lids are made of polyethylene^[3].

Their uses and handling methods differ. Covering with a polyethylene lid provides airtightness, making it good for stacking and storing vegetables or marinated meat in the refrigerator. On the other hand, the rigid and flat stainless steel lid serves as a secondary tray to hold prepped ingredients, or is lightly covered to prevent foreign matter from getting in during cooking. There is also a difference when cleaning. Except for the polyethylene lids, the stainless steel parts are dishwasher safe^[4], so they can be easily washed at high temperatures even if smeared with seasonings. hmmm, it is a clever division of materials suited to two situations: on the countertop during cooking, and inside the refrigerator storing ingredients.