Billiard chalk holders
3D Printed and are much stronger than the cheap ones that come on most chalk holders.
Made of FLEX TPE filament, a tough flexible material with high elasticity. Two split rings and a saltwater Ball Bearing Swivel. Fits Kamui Roku 6 Chalk, does not come with chalk. 

Kamui Roku 6 Chalk Holder

!!NO CHALK INCLUDED!!