3/8-16 Zinc Round Base T-nuts
A really deep ( 3 finger pads ) 2 finger pocket.
Flip it over for a 1 1/2 pad pocket.
Jug #3 is a monstrous hold. It almost feels like a cobble to me. Your hand lies nice and evenly on the hold with your thumb wrapping around the side. It's a full 3 fingers pad deep.
Note the profile photo for how deep the incut goes back.
Sold as a set of 2 holds.