Safe and Strong in every Position Large control elements also for glove operation suitably. the M8 - Connecting system allows to vary fast and simply the arm in the length. Available in the lengths 160 mm, 210 mm and 260 mm in each case with ball or M8-winding hole available. spring supported clamps for simple operation.Two-stage clamp connection. stage 1: O-ring braked stage 2: clamped ball .