This chalk holder is intended to be used with standard square-shaped chalk. Chalk is NOT included. Designer / craftsman : John Leitch. Chalk Shark Development Story: As a pool player, Mr.John Leitch noticed other players' personal chalk holders lacked in design, manner of use and sought to make something better and unique. Various models were made over the years until he discovered the TWO MAGNET system for strong holding power. The present model, using an aluminum disc with leather inlay, incorporates all the best features developed in his studio.Disc diameter: ~4cm/1.6" -Clip length: ~5.5cm/2.2" -Clear case: ~6*5.5cm/ 2.4" x 2.1" -Net weight: 56 gr/~2 oz. -Gross weight: 62 gr/~2.2 oz.