The TriOn is the only invertible pen grip — Large and Medium sizes invert to provide a choice of grip shapes: the Standard (rounded triangle) or the contoured Cloverleaf. TriOn: two grips in one! Molded of surgical silicon gel (no latex). Stretchy surgical silicon material has enough “give” to slide easily onto the pencil or other tool and remain securely in place.
Available sizes: Small (6mm external diameter: fits many computer styluses and small craft tools such as watercolor brushes and knitting needles).
Medium (12mm external diameter: fits standard pencils and most pens)
Large (18mm external diameter: fits markers/many crayons/thick pens)