The two spring springs RSAD have the great deflection of the springs and the casing of cast iron that works as an exoskeleton and protects the spring from sudden movements of stoppages and starts of the equipment or of abnormal vibrations. Its anti-slip rubber base also performs the function of absorbing vibration and noise. To increase the load of these supports can be put a inner spring C99L lilac that gives 130 kg. more load with the same deflection. Comply with ASRHAE, book Applications, chap. 47, sec 47.44, type 4 “Restrained spring isolators”.