This Shim Set from DZOFilm allows you to install Koop rear filters onto your Vespid or Catta Ace lenses with a tight fit. The set comes with eight shims to ensure the filter is installed tightly to prevent any play or wiggle when installed on the camera. Each shim has a slightly different shape, and the thicknesses include 0.5, 0.3, 0.1, 0.05, 0.03, and 0.02mm.