Eazy wheels help you move your Birdy around while folded. The small diameter of the EW1 and EW3 models is perfect for those that only need to move the bike through short distances, while the big diameter eazy wheels EW2 are ideal for longer distances through more rugged terrain. The extensible axle EEWB2 (sold separately) offers extra stability when attached to the eazy wheel bracket for those who need the peace of mind of knowing the their precious bike would not ever fall to the ground.