Think “Strengthened guides”
To keep an ISO cylinder, the guide unit remains unavoidable, but guide rods are generally not enough sturdy compared to the capabilities of the cylinder.
Worse, to have sturdy rods to resist to external forces, you must over-size the cylinder!
With our Strengthened series and Heavy series, you not only have guide units with biggest rods than the Classic series, but also a more robust plate / rods connection to withstand lateral loads, torsions, thanks to a better embedding of the rods in the plate.
Thus, you keep a smaller cylinder, the guide is less bulky, and the price of the system is cheaper.