I HAVE HUNDREDS OF TIE TACKS, TIE BARS AND CUFF LINKS. tie tack/bar: 1.99" x 0.30" (approx. 2" x 5/16" or 50.5mm x 7.5mm). collar bar: none. 0.25" = 1/4" or 6mm - pretty small for standard button holes.
This product would be a great fit for those looking to add an elegant touch to their ties, perhaps for a special occasion or a formal event.