Flexible Damper Belt Link (5 Pack)

Have a 3-zone Aprilaire system that is 12 years old when several of the dampers stopped working. Contacted my standard HVAC contractor who after an hour of so called 'diagnostics' (turning the different zones on and off) to learn what I already told him, told me his company would have to get back to me with a price to fix the system. 2 weeks later, the company calls me and says the *entire* Aprilaire zone system needs to be replaced (controller, dampers). Wanted $5000. Told them that it's either the damper motors or the flex link band on the dampers. No need to replace the dampers or the controller (24v was going out when requested). HVAC contractor said that their "expert" recommendation is to replace the whole system because Aprilaire doesn't make the parts anymore since the system is over 10 years old. If you're reading this, you know that Aprilaire's damper design hasn't changed and the motors are universal motors, so either the HVAC company is incompetent or they're bunch of crooks. My vote is the latter. So, instead of $5000, paid $22 for a pack of the flex links and some manual labor, and my system is operational again.

Apparently my belt was broken a long time without knowing it. Didn't want to replace the whole unit just because of a broken belt but a service call would cost nearly much as replacing the entire unit. Got lucky on getting a part number for the belt. Found the belt here at a good price. Very happy with the purchase. Inexpensive part so bought spares and I will periodically check that the damper is actually opening. Why do they break? Unit should have been designed to use a metal chain.