Sphinx not only are you abrasive and annoying here, you are incorrect as well. The 500 accepts mountaineering boots just fine. It is the carbon fiber/plastic version of the 404, and has recently been rev'd to the 505. All have wire bails in the front, all work with mountaineering boots. I have used the 500's with great success for awhile now. It is nothing like the Diamirs, and serves a different purpose.