This is a pack of two Enduro 24x37 ABEC-3, Sealed Bearings. Specifications: Outer Diameter: 37mm Inner Diameter: 24mm Width: 7mm Seals: LLB Type, Silicone Bearing Info: ABEC-3 Grade ABEC-3 bearings are the most economical bearing Enduro offers, but are extremely tough and durable. Grade 10 chromium steel balls are within 10/1,000,000 round. These are twice as round as the industry standard. 52100 high carbon chromium alloy races go through a vacuum de-gassing process resulting in the purest chromium alloy steel, hardened to R-62. Keeping everything together are riveted steel retainers and sealed with LLB type seals.