Brand new, never out of box: Javelin Pro Hunt Tac Bipod
(SPECS)Bipod ships with a magnetic adapter that replaces your sling stud. They also sell adapters for whatever platform—Picatinny, M-Lok, etc.
I run this same bipod and I love how simple it is to switch between rifles or stick in your pocket/backpack when you don't need it.
I bought a rifle that included a shop credit and ordered this bipod with that credit. It is supposed to arrive 12/18.
$260 cash, FTF at Bass Pro Grapevine. Will ship on your dime.