Frame with 6 or 8 aluminium ribs, profiled mast, top 38.4 × 1.2 mm, bottom 39 × 1.5 mm, crank drive and "twist" rotation mechanism for stepless tilting. (Without Z base, min. 30Kg / max. 55Kg and Z mounting tube Ø 35 / 38-39 mm, to be ordered separately).