rotation,rigid caster can not rotate.Typically two kind of casters are usually used together.For example the structure

of the front trolley have two fixed caster wheels,and the rear caster are swivel casters.

The core technology is the loading capacity of caster wheel.

1.Caster dynamic load is the load weight when moving casters.The dynamic are difference due to different wheel

material,especially the structure and quality of bracket are able to shock and vibration

2.Caster impact load,the moment caster bearing capacity when the device is subject to shock or vibration

3.Static load of casters,the loading capacity when casters in the stationary state. As regular exercise load is 5 to 6

times as the static and at least 2 times of impact loading.