This is a set of three loaded six-sided dice weighted to roll sixes, specifically designed for rolling up 18 stats for your D&D characters. Let's be clear here: when you use these dice to roll a D&D or Pathfinder character, you are cheating. Blatantly and flagrantly. There is no excuse for this, except possibly if your GM is evil and cheats as well, killing off characters unfairly, and using these loaded dice is just the next step in the escalation that will inevitably lead to rage-fueled table flipping, dice throwing, and eventual man-hugging as you become cool with each other again.
These are standard-sized black six-sided dice with silver pips for numbering. They are numbered normally, but are weighted so that they're more likely to roll six. They won't always roll six, but are far more likely to. In general the longer they roll, the more likely they are to land on six -- after a short drop they'll land mostly on whatever face is up, but after a nice long roll they'll usually come up all sixes. If you want to be extra sneaky you can mix one or two of these in with some other dice, just to slightly edge things in your favor without being super blatant about it.
With a little bit of practice you can pretty frequently get a natural 18 on a roll of the three. The dice will easiy pass casual examination, but anyone who picks them up or rolls them a bunch will pretty quickly realize that they just about always roll sixes.
To reiterate from the intro, just in case you're trying to justify that somehow using these dice is not cheating, be aware that you aren't fooling anyone. Except people who don't realize what you're doing. Loaded dice are cool and fun to play around with, but using them in a game is breaking the rules.
WARNING: CHOKING HAZARD - Small parts. Not for children under 3 years old.