Amazon.com: LONSEL Dovetail to Picatinny Rail Adapter 11mm Dovetail to 21mm Picatinny/Weaver Rail Convert Mount - Low Profile Scope Riser Rail Adaptor - Base Mount 3/8" to 7/8" Converter (1 Pack) :
Picatinny Rail Ball Head Adapter (Arca-Swiss Plate) -
Amazon.com : Caldwell Pic Rail Adaptor Plate with Durable Construction and Picatinny Rail Attachment for Outdoor, Range, Shooting and Hunting , Black : Sports & Outdoors
Hawke Sport Optics 2-Piece Riflescope Rail Adapter for 3/8"