MITRED DIAMONDS aka SUNKEN BUTTONS 4-part caster. Found In Lechner's The World of Salt Shakers III page 264 in the two knob style, the maker is unknown. circa 1883-1890. It is 5-5/8 SQ x 6-1/2 tall x 2-3/8 wide handle x 2-1/2 collar below the handle. Sunken Buttons (Kamm 4-129, Peterson Salt Shakers 40-S, Bredehoft Tumblers 44), Wallace-Homestead Price Guide to Pattern Glass 11th Ed.-255). Mitred Diamonds (Lee VG Pl. 31; Metz 2-216). Pyramid (Millard 2-Pl. 35). Millard's Pyramid (Unitt 2-162). There's another by Jenkins "A Fortune in the Junk Pile" but I don't have the book so don't know which name was used. And of course Lechner III-264 Triangle, Inverted which will probably be added to some reference as Inverted Triangle.Inez