Balluff BNS 519-d5 d12-100-11 Limit Switch New item . Never used. No original box or paperwork. Mechanical row-position counters with up to 16 switching points are the classics of automation. The switching process is carried out by a telescopic ram. This ram is used to connect a mechanical switching element in a separate sealed chamber. The optimal choice of ram shape for the application in combination with our cams guarantees a long service life.