Product info:

This is a pack of ten 8x16x5mm High Speed "HS" metal shielded ZZ 1/8 wheel bearings from Ultimate Racing.

These 8x16x5 bearings are the standard bearing for 1/8th scale off-road vehicles, both for internal bearings in the diff cases as well as external wheel bearings. Please check the manual that came with your vehicle for the correct size if you are not certain.