Exodus 28:2

“…the twelve sons of Jacob, from whom also sprung twelve tribes,— the breastplate of the high priest, which bore twelve precious stones and twelve little bells,—the twelve stones which were placed by Moses at the foot of the mountain,—the same number which was placed by Joshua in the river, and again, on the other…” — editor's note: Ex. xxviii. 2.—There is no mention of the number of the bells in Scripture.