LEG EXTENSION AND CURLWe set a height adjustment under the seat and can make a comfort height when do lying leg curl workout. After long-term testing, the function is real, effective and comfortable. MATERIAL & WEIGHT: 50*50mm carbaon steel, 1.4mm thickness pipe as main frame pipe, ensure the steady form when you do workout. Our leg machine net weight is 21KG, 660LBS weight capacity, far beyond home use standard.