Exodus 26:19-21

King James Version

¹⁹ And thou shalt make forty sockets of silver under the twenty boards; two sockets under one board for his two tenons, and two sockets under another board for his two tenons.

²⁰ And for the second side of the tabernacle on the north side there shall be twenty boards:

²¹ And their forty sockets of silver; two sockets under one board, and two sockets under another board.