The brand is "outdoor connection" and I've seen them in amazon, eBay, and here https://www.boytharness.com/products/the-outdoor-connection-titan-q-r-sling-swivels?srsltid=AfmBOorFU8tLHP3OWwkOv5yrX-IiSkplbl8c3O7Z78WOlLp_vLmOe7gc
Kinda pricey for sling swivels, but they are quiet, low profile...