Material: lightweight and sturdy ABS PLASTIC. Pakage inclues 50 grommets. Inside Diameter: Approx. 41mm/1.6". Outside Diameter: Approx. 70mm/2.8". Fit for rods up to 1-1/2-inch diameter. Lightweight curtain grommet makes it smoothly slide on curtain rod and protect the rod with low noise. The diameter of the holes which is cutted on the fabric is 51mm/2". No tools needed for installing, snap together easily by pushing one half into the other. Great accessories for holding curtains and draperies. Widely use for DIY to decorate your curtain, drapery, fabric, etc. Note:These curtain grommets suitable for general thickness and weight curtain.