The wheels, tires, rollers, magnets, & the motor can that I use are from China. The can is from Hot Speed & the magnets are from Tianhao (V2).
Like Thai racers, their tires are made of the sponge sole slippers. And most of them use 21mm rollers.
Unlike mine, I use 19mm teflon rollers for the upper & 18mm alloy rollers for the lower.