They are to wear linen turbans on their heads and linen undergarments around their waists. They must not wear anything that makes them perspire.
KJV
They shall have linen bonnets upon their heads, and shall have linen breeches upon their loins; they shall not gird [themselves] with any thing that causeth sweat.
ASV
They shall have linen tires upon their heads, and shall have linen breeches upon their loins; they shall not gird themselves with anything that causeth sweat.