Specna Arms 7mm Bushings

Your bearing size is determined by your gearbox shell - if you have a 7mm gearbox then you can only use 7mm bushings/bearings, as no other size will fit. These are 7mm bushings, universally regarded as the best for general airsoft use.

Bushings are more reliable than bearings, although they run louder. This is due to the fact there are fewer moving parts, so less to breakdown

Fitting bearings to your gearbox requires complete disassembly - if you are at all unsure, please seek the aid of a professional