Free Standing Spring(FDS) Vibration Isolators consist of high deflection, free-standing, unhoused, large diameter, laterally stable steel springs assembled into an upper load plate and leveling assembly. To assure stability, the spring isolators have lateral spring stiffness greater than 1.0 times the rated vertical stiffness and are designed to provide a minimum of 50% overload capacity. Springs are polyester powder coated, with a 1000-hour salt spray rating per ASTM B-117. In lighter capacities, FDS Spring Isolators have molded neoprene bottom load plate assemblies. In heavier capacities, springs are welded to the load plate assemblies and are furnished with a neoprene noise isolation pad. FDS isolators have provisions for bolting the isolator to the structure. FDS isolators are available with deflections to 4" (102 mm) and with load capacities to 23,200 lbs. (10523 kg) as standard products. Custom isolators with higher deflection and greater load capacities are also available. Acoustics Spring Isolators are highly effective for control of both high and low frequency vibration produced by reciprocating air or refrigeration compressors, pumps, packaged air handling and air conditioning equipment, centrifugal and axial fans, internal combustion engines, etc.