Often used for the Magpul paraclip, please see the link below.

https://diggertactical.com.au/products/magpul-paraclip-for-sling

The RSA provides a low profile forward sling attachment point for the Magpul MS3® or MS4® and other clip-in systems. Made from QPQ salt bath nitrided steel for wear and corrosion resistance, the RSA attaches to any 1913 Picatinny rail.  It has has passed stress tests of over 300 pounds while weighing in at a mere 1.3 ounces.

Made in the USA.

LOW PROFILE, UNOBTRUSIVE DESIGN

All steel construction

Case hardened and finished in QPQ salt bath nitride for extreme resistance to wear and corrosion

Flat rate express shipping Australia wide $16.99