Aeroflex - Your Checklist Ring Solution From Aerobind: The Aeroflex checklist ring is Aerobind's checklist ring solution for pilot checklist, pilot QRH and FCOM manuals. Now the durability and reliability of a stainless steel core is available at the price of a nylon monofilament ring. These rings feature a ball-in-socket clasping mechanism with a braided stainless steel core coated in clear polyurethane for unsurpassed durability that won't rust or scratch. Trust Aerobind for your locking ring solution. 6 Inch ring circumference; 5 per package.