SIEMENS3RH29111HA11 Auxiliary Contact Block, IEC Style, 1NO+1NC, Front Mounting, for Use with 3RT2/3RH2 Size S00-S3, Screw Terminal

This unit snaps on to the back of many Siemens contactors. They can be found in a lot of commercial equipment & HVAC systems worldwide. It can switch auxiliary circuits or provide status monitoring to controllers.We have a high-end $13,000 Keaser air compressor. In our case, it monitored the contact for its physical state & when it broke, it told the computer the contactor wasn't functioning and went into protection mode.Delivery was quick...got it next day. Our compressor being down was costing us $50-60,000 US in sales each day! So this was a life saver.The old unit literally pops of when you pull up the spring clip and slide it over. Swapped the wires, slid the new one in and DONE! This part and its repair would easily have been a $300 service call.