Just wanted to give credit to MI for their excellent customer service.

I have a MI ERS (emergency rear sight) on my Stag AR.
I noticed that after a few rounds at the range, a pin (the axis which the sight moves from the up or down position) would rattle loose and come out about halfway.

So, the other day I decide that I'm going to put some lock-tite on said pin to prevent it from rattling back out. I pull the pin all the way out and all hell breaks loose. There is a spring loaded detent riding on a small steel ball that provides the locking mechanism for either the up or down position.

Upon taking the pin out, parts fly everywhere and I am unable to locate the spring.

I call Midwest Industries, explain my situation and ask if I can purchase a replacement spring.

The lady on the phone informed me to send the whole sight back and it would be replaced, because she wanted to insure I didn't have the problem again with the pin sliding out.

I must say, I was very impressed with the level of customer service from Midwest Industries.