Sinclair Double Sided Porcelain 48 Gas Oil Vintage Collectable Sign. The item "Sinclair Double Sided Porcelain 48 Gas Oil Vintage Collectable Sign" is in sale since Monday, December 28, 2020. This item is in the category "Collectibles\Advertising\Gas & Oil\Merchandise & Memorabilia\Signs". The seller is "qualserv" and is located in Jefferson, Iowa. This item can't be shipped, the buyer must pick up the item.