The 63mm x 45mm Hot Spot is a small, super-agile version of our 69mm and 76mm Hot Spot shapes. Molded around our advanced Mini-EC hub, its a light, quick, do-it-all wheel ideal for general-purpose cruising, surf-skate, and Tight / Hybrid slalom. Not too big and not too small, the Mini-EC hub preserves ample tire thickness while saving over -ounce per wheel, stiffening the inside edge, and super-charging inside edge rebound. Features: 63mm tall x 45mm wide HOT SPOT Wheels Durometer 83A 43mm running surface Offset bearing seat Square outside edge, beveled inside edge 4.0 oz. each Sold in sets of Four wheels Available in TWO proprietary formulas, with finely-tuned durometer choices. Defcon ultra-high-rebound formula: Guinness WR speed Easy, predictable slide (even on concrete) Long-lasting grip Slow, consistent wear Fast, smooth, and lively underfoot. An optimal balance of properties for most surface conditions. BlackOps: comfortable and predictable on all pavements Exceptional balance of speed and grip Extreme traction fresh Buttery and smooth sliding broken-in