Here's a newly discovered unlisted oil reservoir insulator. Not in any of the books or NIA website! Measures 3 3/4" tall x 4 1/8" wide. Has 3/4" pinhole. The base is completely flush. Unmarked. Found in Spain, but likely British made.

Excellent condition with only 2 super teeny wire groove flakes and a small light rough spot. Some sulfur cement in pinhole. Easily VNM+.

First email that says they will buy it gets it for $500 plus 8.40 postage. Optional insurance extra. Thanks!