Ruger 10/22 Weaver Scope Base Adapter, Blued, Brand New. Shipping by standard letter mail for $1.65, nationwide (price of stamp).

Combination Weaver and tip-off Ruger 10/22 scope base adapter, uses tip-off or Weaver-style rings. Black powder-coated aluminum. Includes 4 screws for assembly. Weighs 33 grams (with the 4 screws), and is 5mm thick, so ships by standard letter mail anywhere in Canada for $1.65 (price of a stamp).  Genuine Ruger Factory Accessory. Came with my 10/22, never used, don't need it. Thanks for looking!