Spare HX2 Heelys wheel kit for one pair of HX2 shoes. The HX2 series are Heelys with 2 wheels per shoe.
Notice:
Small fits Heelys:11-5 (UK) / (29-36,5 EUR)
Medium fits Heelys: 6-7 (UK) (38-39 EUR)
You can always see what size is needed for your specific model if you pop your wheel or plug out of the shoe and have a look at what it says.