Parallel sided coil with loops piercing the return tube which when theoretically cut gives a pair of 13- twist Mobius strips.

A single surface model made by Alan Bennett in Bedford, 1995. It consists of a parallel sided coil with loops piercing the return tube which when theoretically cut gives a pair of 13-twist Mobius strips. A Klein bottle has no edges, no outside or inside and cannot be properly constructed in three dimensions.