Assemby is easy: roller has grooves on both sides, user can set the roller belt on any side desired 80mm diameter roller offers natural resistance automatically Features shorter legs that provide a 25mm lower virtual floor level, and it will allow users to ride more easily Fits most 24 - 27" and 650c - 700c wheels For fitting various sizes of bike wheelbase, the front roller is position adjustable in 5 levels and the rear roller in 2 levels The MozRoller is the combination of the 80mm diameter roller drum and the triple folding type frame for more compact storage. Assemby is easy: roller has grooves on both sides, user can set the roller belt on any side desired 80mm diameter roller offers natural resistance automatically Features shorter legs that provide a 25mm lower virtual floor level, and it will allow users to ride more easily Fits most 24 - 27" and 650c - 700c wheels For fitting various sizes of bike wheelbase, the front roller is position adjustable in 5 levels and the rear roller in 2 levels