Protect your aquarium against evaporation and jumping fish with these clear glass lids. Each glass cover includes a set of four plastic mounting clips and provides a perfect fitment for each respective tank. Please keep in mind that these glass lids cover the majority of the open top of the tank leaving a 3/16"" space on each side. If the glass lid panel is mounted towards the front of the tank, this leaves a 3/8"" gap between the rear of the glass panel and the back of the aquarium. We recommend using an internal filter if incorporating a glass lid to your set-up.