This is the longneck version of the Qu-ax freestyle frame. The extra long seat pipe brings stability; therefore your short seat post can not be bent as easily. The Clamp, now being placed closely to the seat, helps the stop those scratches and will not cause anymore bruises when doing Stand-Up tricks.

•  20 inch
•  Chrome-plated
•  Bearing distance: 100 mm (middle to middle)
•  Inside diameter: For 25.4mm seat posts
• Outside diameter: For seat post clamps with a 28.6mm inside diameter

You should at least have this inseam length to be able to ride the frame.

320 mm: 76 cm
420 mm: 86 cm

Under the assumption, you are using 114 mm Cranks and a flat Freestyle saddle. By use of other components, the values should be changed accordingly.