Bearings are priced each. Sets of 16 bearings are for all quad skates and 4-wheel Inline skates. Sets of 20 bearings are for the 5-wheel Inline skates.  All Inline skates use 8mm bearings.  Quad skates could be 7mm or 8mm depending on your axle size.  Call us if you need help determining the bearing size you need.  Order Online via our Secure Server or call us at 1-800-595-8560 to place your order.  We can answer any technical questions you have concerning your order by contacting us via Email or ask us when placing your order via telephone.