This rugby spring comes in 2 different sizes (coil wire diameter size) of 3.5 mm and 4.0 mm. 3.5 mm size is caters for child weighing from 3-10 kg and 4.0 mm is for those weighing above 10 kg up to a maximum of 20 kg. 

Packaged along with this rugby spring is a safety belt which is to be used together with the spring. Instructions on the installation of the safety belt must be strictly adhered to.

To obtain maximum safety and comfortable bounce of the spring, the length of the safety belt from the hanging point of the spring cot frame to the hanger should be 24 inches. Due to wear and tear, the safety belt needs to be replaced from time to time.