feature the Standard IPS, for adults and teens, which can be used by anyone, whatever your weight (min weight 70 lbs - 32 Kg). No problem if you are a heavy person. If your weight is well above average, you will however get less rebound effect and might consider opting for a Pro model.

feature a quite harder IPS. It is suitable for heavy weight individuals and/or athletes who want a harder workout or do extreme sport.

feature a softer IPS suitable for Juniors, boys & girls, weight from about 40 lbs (20 Kg) to about 120 lbs (55 Kg), sizes 1-6 US boys, 2-7 US girls - EU 33-39.
If your foot size is larger or/and you weight is on the higher side, you should consider the XR series.