The SnakePick, coils around the player's finger at an outward taper. The necessary tension is created by the coil sizes in relation to the finger. The medium 15mm (1.5cm) size is measured based on the width of your finger, closest knuckle to the fingernail, and generally fits young teenagers and a lot of female guitarists.
The SnakePicks gauge density is not set by a measurement like the standard pick but set by the consistency of the plastic material. This revolutionary idea works magnificently and allows the guitarist to have much more definition and control over his or her playing without losing tone through alteration of their technique. The hard gauge density has been set to emulate what guitarists believe is a good "hard" pick.