New Robot Fish Activated Turbot Electric Shark Water activated / swim sensors .Color : Red,Blue,Green,Gray Built-in energy saving mode. High simulation, as true fish floating and sinking combined free floating Life-Like Tail Fin Motion. Each fish includes 4 LR44 button batteries (2 in fish and 1 replacement set) Powered by 2 x L1154 button batteries. Dimensions: 7.5 x 1.8 x 3.5cm. Weight: 18g Feature: Robo Shark have motorized tails with a realistic swimming action to propel them through the water. They will also try to avoid colliding with the sides of their tank because of the tiny sensor at their heart. The Robo Fish is battery powered, with each pack coming with an additional set of batteries in case your Robo Fish runs out of juice.