An Ateco 6-piece plain square cutter set (5253). Graduated stainless steel. Official page: cutters range from 1.38" to 2.63" and are 1.25" high. Made in China. Specs from Ateco's 6 Piece Plain Square Cutter Set page (the catalog table prints height 1.1"; copy follows the live product page).

Six nested stainless squares. Cookies, fondant, pastry.