Exodus 26:25

And they shall be eight boards, and their sockets of silver, sixteen sockets; two sockets under one board, and two sockets under another board.

Cross-reference

Exodus 26:19 specifies the silver sockets for the boards, part of the same construction instructions.

Exodus 36:30 records the actual construction matching these specifications exactly.

Exodus 38:27 details the silver used for the sockets of the tabernacle, connecting to the materials here.