The 20 gallon tank divider is suitable for 20 gallon long tanks. It's made from a solid material with adjustable sidebars. The clips are used on the rim of the tank for added stability. The divider does NOT work in rimless tanks unless siliconed in place. The divider works best in a tank with substrate; it may not be suitable for bare bottom tanks. It comes with a full instruction sheet and video link to help with installation. Things to note before buying: These dividers are not flimsy and have been made with Betta Fish in mind. You will require filtration in each section to help with water flow. **Sale is tank divider only *** All Betta fish may not be suited to divided tanks.