tritium night sights for sig sauer p250

[sidearmstevo]

I havea sig sauer p250 that has sucky 3dot sights. I would like to replace them with adjustable night sights, probably tritium. Can someone tell me the difference between tritium night sights and other kinds of night sights? Also, who makes quality night sights that wont break the bank? Warranty is very important to me. Any info will be greatly appreciated.