These are rollers for making Yaen (a type of fishing lure) yourself. There are 6 pieces. They have been tested in actual fishing several times. They roll very well. They are thicker than the rollers I have listed before. The hole diameter is 1.2mm, and a stainless steel rod can pass through. 1.0mm rods also work well. There are 22 colors available. Please specify your preferred number after purchase. The quantity of each color can be different.