This is a holder on which you can hang the parts necessary for making devices.The safety pin is removable, so it is easy to replace and the fabric is not easily damaged : (1) Lightly press the convex part of the slit on the back.(2) Slide the safety pin and pull it out.Size: Height 35mm (including upper round hole parts) x 50mm(thickness 6mm);Width: 50mm;Thickness: 11mm (including 4mm back hook)