Abstract: A structure for securely mounting and protecting electronic devices within a housing or tank includes two supporting plates connected to two mounting pieces. The supporting plate defines a first hole, and the mounting piece defines a second hole. A fastener through the first hole and the second hole will position and hold the mounting piece on the supporting plate. The two mounting pieces position the electronic device. The mounting pieces are adjustable relative to the supporting plate, so the distance between two mounting pieces is fully adjustable to fit and hold electronic devices of different sizes. A tank or housing using the structure is also disclosed.