Based on the H series castor these shock absorbing castors do not use coil springs but one or more stacks of disc springs that are assembled in various combinations to give a wide range of load ratings.
The table shows wheel movement and maximum load for good to average conditions.
When fitting at 120 x 60mm hole centres use 12mm diameter bolts
When fitting at 105 x 80/75mm hole centres use 10mm diameter bolts