A bicycle crank fixing structure is arranged to fix a left crank with a mounting bore and a slit extending radially from the mounting bore to a crank axle. A method for generating a parts catalog consisting of a parts list and corresponding disassembly illustrations is provided. The data port assembly and simplex receptacle assembly are receivable within a channel support through ends of the channel support and are positionable in desired positions along the length of the channel support. The pivotable second section enables the cleaner to negotiate sharp corners between a floor and a wall of the pool and further lengths a wheelbase provided by the first section during reverse motion of the cleaner. The invention relates to preparations and compositions of the present compounds and their use as medicines.