Magnetic switch plug for cable 4.0 - 6.0 mm, suitable for make contact type RC27-1S. With LED indicator (yellow) when contact closed. Buschjost article no. B0040.000178 For all valves with optional end position indication, ending -EA, X2. The LED helps to detect at first glance when the contact is closed , which can be very helpful when adjusting the end positions.Easy to check the switching status on site. This item is osolete. Alternative: RC27-S with integrated LED status indicator.