Other so-called PU castor, the central metal pin will be self-spined and will be self-motioned after certion period time of usage, and the 2 sides of wheel will be frictioned with the center. The 2 wheels will be detached over time.
Hun Tai's PU castor's central metal pin has knurled processing for fixing purpose without any self-motioned. 2 sides of wheel will not be motioned with central metal pin and will not be frictioned with the center, so that the 2 wheels will not be detached over time.
With the knurled processing applied, it has over 10 years life of usage. Without the knurled processing applied, it only has about 5 years life of usage.
For the material, other so-called PU castor might use low cost material such as PVC, TPR or TPE. The high cost real PU material is applied on Hun Tai's PU castor. It makes longer life of usage and it rolls quieter.