Numbers 4:6

And they shall put on it a cover, even a blue skin, and put on it above a garment all of blue, and shall put the staves through [the rings].

And shall put thereon the covering of badgers’ skins, and shall spread over it a cloth wholly of blue, and shall put in the staves thereof.

put a covering of sealskin on it, spread a blue cloth over it, and put in its poles.