Insulators as follows -- actual postage additional:

U-164 super cool unmarked piece! base bruise creates some short stress lines but no porcelain missing -- tough U number! $35 (SOLD)

Awesome blue mottled glaze signal -- base rest -- glazed pinhole - no issues -- $12

U-648 tough U number, especially in cobalt blue! no issues -- $60 (SOLD)

U-474 awesome light tan - nearly yellow! no markings or issues -- $15