Radar Energy wheels - pack of 4, 62mm 78a perfect outdoor wheels. 

These are exceptionally brightly coloured urethane wheels that bounce over twigs and small stones. They have more of an 'edge' to the wheel, rather than rounding off as the Moxi wheels do, so can feel more stable.
 
*Please note - Some of these variants available for pre-order are in stock with a UK supplier so will take an addition 4-5 days for delivery.