1 Kings 7:30

Overview - 1 Kings 7
The building of Solomon's house.
Of the house of Lebanon.
Of the porch of pillars.
Of the porch of judgment.
Of the house for Pharaoh's daughter.
13 Hiram's work of the two pillars.
23 Of the molten sea.
27 Of the ten bases.
38 Of the ten lavers,
40 and all the vessels.
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1 Kings 7:30  (King James Version)
And every base had four brasen wheels, and plates of brass: and the four corners thereof had undersetters: under the laver were undersetters molten, at the side of every addition.

Ezekiel 1:15-21 ; 3:13 10:10-13

had undersetters
It is probable that these undersetters were so many strong legs, somewhat shorter than the wheels, and were intended to prevent the laver from tilting, or falling, in case of any accident.