This sells on the Brownells website for $39.95. Comes with a spacer to put at the end of the buffer tube, since it slightly lengthens the stock...and a longer screw to use with it. It has been installed
but not used, as you can see from lack of wear.
Gives Your Fixed-Stock Rifle The Versatility Of Quick-Detach sling Mounting
Low-profile adapter gives an AR-15/M16 with an A2-style buttstock the convenience and versatility of single-point clip-on sling attachment. Lets you combine the stable cheekweld of a fixed rifle buttstock with the ease of the latest, quick-attach tactical slings. Precision machined from 4140 carbon steel for extra strength, with extra metal on the attachment loop, so no matter how hard you pull or twist the sling, this adapter won’t break. Right Hand (RH) model has the loop on the left side to accommodate right-handed shooters; Left Hand (LH) model has the loop on the right for left-handed shooters. Requires no permanent alterations to rifle: simply remove the buttstock, slide the adapter over the receiver extension tube, and reinstall the stock using the included spacer and extended buttplate screw.
solid aluminum construction, thick and sturdy
remember, it's for the fixed stock, not, as far as I know, for the collapsible stock.
$ 25 shipped...