The four extension tubes 9, 17, 34 and 67mm, usually seen as a set of four, and the 22-68mm zoom extension tube may used either single or in any conceivable combination among themselves or in conjunction with other dedicated accessories, such as bellows and the reversing adapter.
The universal Rollei bayonet mount and its ten electrical signal contacts fully guarantee the perfect interaction between the camera and the lenses.
The lengths of the extension tubes are based on the mechanical features of the 2.8/80mm standard lens, which is likely to be the most frequently used lens for this type of work. With 9mm, the shortest of the tubes is equivalent to the extension of the helical focusing mount of the lens (which is actually 8.63mm). Together with the 9mm tube, the lens can extend up to 17mm, which is the size of the next extension tube, and so forth to 34 and 67mm.