08/05/2007 - by Le Nguyen Tran from Stafford, TX US
I have a low profile A.R.M.S. flip-up for my rear iron sights. I was having a problem getting the 3X mag to fit over the iron sights. I later added the Aimpoint Twist Mount Spacer to get 1/8+ of inch height, which was just enough clearance over my iron sights. Afterwards I was very pleased with the product, couldn't be happier.