To ensure double guarantee for the beam loading, we recommend to use two piece of loading chain  for each side .One is for loading the other is for safety ( This safety chains  should be one or two cm longer than the loading chains.)  But we need an Extra Charge,for the safety loading chain is 5.7USD/PC.Increase the safety lanyards is OK, incur additional costs, the average price of 5.7USD / PC.