【4 sets of Double-Layer Springs】The Super Push Down Bar is made of exercises-specific carbon steel springs with long lasting elasticity,which are extremely uniform in compression,thus stimulating the muscles to maximize gain.Unlike other traditional upper body workout equipment,ours is engineered from 4 sets of double-layer springs instead of 2 sets of single spring,which offers large load-bearing capacity and more safe and durable to withstand the most challenging workouts!