I HAVE HUNDREDS OF TIE TACKS, TIE BARS AND CUFF LINKS. tie tack/bar: 1.86" x 0.80" (1-7/8" x 13/16" or 47mm x 20mm). collar bar: none. I always try to point out any clear blemishes and condition. 0.25" = 1/4" or 6mm - pretty small for standard button holes.