This is a fun fidget idea that I had after seeing so many gravity knife fidgets floating around. The erasers are available just about anywhere. The hinge uses M2.5 x 8 screws. The main body (Sheath) has holes for heat-set inserts, but they are not completely necessary. Print 2 pins and one of each other part. The pins fasten to the eraser holder with M3 x 6 screws. Happy printing!