It is a frame with measurements of an inner cover which has a drawer in it. It is used on top of your stack of supers to deliverPara-Moth (sold seperately) when you store them for the season. You pull the drawer out and you put your para-moth on it. When you have to check the chemical in 3 weeks, just pull the drawer out and add more if necessary. The drawer stays in place on top of the stack and makes the chore of checking and adding additional para-moth a breeze. The Para-Moth Drawer is well made with weather stripping and will not leak.