Cramp Stop Spray is a homeopathic oral spray containing Arnica, Mag Phos, Cuprum Met and Nux vomica in low potency dilutions. These ingredients are traditionally selected in homeopathic practice for sudden cramping, muscle tightness and spasm support, including period related cramps and restless legs.
The main thing to know before buying is that Cramp Stop Spray is not a magnesium drink or electrolyte product. It is a homeopathic spray designed for quick use at the onset of symptoms, with dosing directions based on repeated short sprays. If that is the style of product you are looking for, the format and ingredient system are both clear.