Prefer a 4-wheel pushchair but still want it compact? then covert your quinny zapp flex or zapp express pushchair with the quinny zapp x 4 medium wheels unit by easily clicking this attachment unit in place of your current wheel unit. using the quinny zapp x 4 medium wheels you can easily transform your 3-wheeler into a 4-wheeler while keeping it compact. additionally if you have the quinny zapp flex plus then you can still have a 4-wheel solution which is more compact