Just acceptable quality: steel bracket is thin with just (again) average bearing & wheel quality. However the price is cheap and you can still be happy if using the caster for light duty as the ball bearing will offer easy manuevering.
Solution to minimize overall height and maximize load capacity. Dual wheel casters also improve stability and swivel more easily than wider-face single wheels. However, this 40mm diameter caster is the most "ugly" one of the Series.