Exodus 36:29-31

Young's Literal Translation

²⁹ and they have been twins below, and together they are twins at its head, at the one ring; so he hath done to both of them at the two corners;

³⁰ and there have been eight boards; and their sockets of silver [are] sixteen sockets, two sockets under the one board.

³¹ And he maketh bars of shittim wood, five for the boards of the one side of the tabernacle,