Lucky Reptile Terra Fan Set TF-1UK is a low voltage mini fan system with temperature controlled fans; depending on the temperature, the fan speed will decrease or increase to allow for optimal conditions inside the terrarium. The base set consists of a transformer and two fans in order that one fan can be used to blow fresh air into the terrarium while the other pulls out the old air. This way an optimal circulation is ensured. The fans are excellent for animals that need high air circulation like chameleons. One transformer can be used with up to 4 fans. Extension fans are available separately.