I HAVE HUNDREDS OF TIE TACKS, TIE BARS AND CUFF LINKS. tie tack/bar: 3.32" x 0.50" (3-5/16" x 1/2" or 84mm x 12.5mm). collar bar: none. 0.25" = 1/4" or 6mm - pretty small for standard button holes. 0.50" = 1/2" or 12.5mm -this is fairly large for standard button holes.