Insulators as follows -- actual postage additional (prices as marked or take all four for $20)

U-113 super crude glaze with cool voids (see pic) -- flat skirt flake -- $5

U-149A tall thin beehive attributed to Pittsburg -- cool trimmer marks on dome! No issues -- $8

U-114 awesome lighter tan glaze! no issues -- $8

U-108 cool toll style -- one tiny peck -- $8