Exodus 36:20-24

And he made boards for the tabernacle of shittim wood, standing up.

The length of a board was ten cubits, and the breadth of a board one cubit and a half.

One board had two tenons, equally distant one from another: thus did he make for all the boards of the tabernacle.

And he made boards for the tabernacle; twenty boards for the south side southward:

And forty sockets of silver he made under the twenty boards; two sockets under one board for his two tenons, and two sockets under another board for his two tenons.