Zoty provide ABEC-3, ABEC-5, ABEC-7 grade 5x10x4mm ball bearings use for RC car clutch bells.
The standard quality ABEC-3 made of full chrome steel, Z2 level, price is cheap, but its good choice, rolling smoothly and low friction for use in Gas cars, clutch bells...
Higher quality ABEC-5 grade made of AISI440C stainless steel races+Si3N4 ceramic balls, light oiled 5x10x4mm low friction bearing with several options to help satisfy anyone's desire. ZZ double metal shields, 2RS double rubber seals or 2RZ one side with metal shield, another side with rubber seals that 3 kind of type seals what makes the bearings can meet the different racers needs.
Rubber seals are great protectors against dirt but the price is that they offer a little more friction due to the tighter seal, may it came off out the bearing when running high speed. the performance of a metal shield is excellent but allows dirt to get in easily. This is the best performance you could attain while maintaining some protection from dirt.
ZZ metal shield ball bearings 5x10x4mm MR105ZZ ABEC-3
2RS rubber seals ball bearing 5x10x4mm MR105-2RS
ZZ shields hybrid ceramic ball bearing 5x10x4mm SMR105ZZ/C