1. There are cracks on both sides which can the flow of water within the tank and isolation box. 2. The 1mm space can avoid the juveniles swimming out and also can their safety. 3. Floating design can be moved anywhere, besides the double-layer is space-saving. 4. Transparent cover can prevent fish jumping out of , and the middle hole is convenient for feeding, it also can prevents adult fish to attack juvenile fish. 5. Comes with high strength suction cup.(The sucker is shipped in white) Colour:Transparent Material:Acrylic Package Contents: 4 * Small incubator 4 * Large incubator Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.