Albert Barnes Commentary 1 Kings 7:30

"And every base had four brazen wheels, and axles of brass; and the four feet thereof had undersetters: beneath the laver were the undersetters molten, with wreaths at the side of each." — 1 Kings 7:30 (ASV)

Plates of brass - This should be translated as “brazen axletrees.”

The “undersetters” (literally, “shoulders”) are thought to have been four brackets, or bars, extending from the four upper corners of the bases and stretching upward to the outer rim of the laver, which then rested partly upon them.

At the side of every addition - This is better translated as “each opposite garlands.” The laver was ornamented with a garland at the place where the support reached it.