John Gill Commentary 1 Kings 7:27

"And he made the ten bases of brass; four cubits was the length of one base, and four cubits the breadth thereof, and three cubits the height of it." — 1 Kings 7:27 (ASV)

And he made ten bases of brass
Seats, stands, or settles for the ten lavers after mentioned:

four cubits was the length of one base, and four cubits the breadth
thereof ;
as broad as it was long, and so a square, that the laver might stand firm upon it:

and three cubits the height of it ;
from the ground plates to the surface, that the priests might be able to reach the layers, and wash their sacrifices.