These wheel bearings are for replacement purposes only. These bearings fit the front caster wheel of all our models. Each front wheel contains 2 (two) bearings, one on each side of the wheel. SOLD INDIVIDUALLY. If you need a bearing on the left side of the wheel, then just order one. If you need bearings for both sides of the wheel, then order two. For example: 1 bearing = $5, 2 bearings = $10.