Sig Sauer KITTRDGRIPHANDSTOPBLK Tread Handstop Kit Black Polymer
https://www.tandktactical.com/shop/798681598854-sig-sauer-kittrdgriphandstopblk-tread-handstop-kit-black-polymer-17643
https://www.tandktactical.com/web/image/product.template/17643/image_1920?unique=45b21f2
This handstop kit includes a both a short and long handstop. The stops are M-Lok compatible and come with all mounting hardware.
