Buying up this UO resist power scroll will max out your resist cap which makes it so monsters can no longer drain your mana. Which is important for just about all classes. Having 120 resist is required in UO if you are PVPing. This allows you to escape paralyzing effects without the need of things like trapped boxes. Another cool effect of having 120 resistance is that blood oath can no longer get you killed. This is a must for most characters to buy.