IDS Digital Dual Scale Aquarium Fish Tank Thermometer Temperature Sticker Easy to install, just peel off the back of the sticker and the transparent protective film at the front and stick it on the outside wall of the aquarium, that is it. Qty: 5 pcs Place on the tank glass outside the aquarium tank Suitable for cold water, tropical and marine aquarium. Size:10cm x 2cm - 3.94inch x 0.79inch.