D10

It's a die. With ten sides. Pretty simple concept.

It's in the shape of a pentagonal trapezohedron. You can stand it on its point and spin it like a top.

Your d10 dice are not this good-looking.

Rolling d100 Using Two d10s

Some Systems require you to roll d100s frequently. There's a better way of doing it than rolling a golf ball with 100 sides.

Get out two d10s. Use one die to denote the singles digit and another die to denote the tens digit. Some d10s have two digits per side (see above) to make differentiating your digits easier, but you can roll d100 with any two d10, provided you specify beforehand which die is the tens and which the ones.

Reading it off is simple. Did you roll a 20 and a 4? That's a 24. A 90 and a 1? 91. A 00 and a 5? Just a 5.

The only possibly ambiguous result is two zeroes: a 00 and a 0. Obviously you rolled a 100. Why? Because the alternative is a 0 which you can never roll with any other die. That, and the system assumes a roll from 1 to 100, not 0 to 99.

Mathematically, each digit is determined in an independent manner. There are exactly 10*10=100 two-digit combinations, all equally likely. You now have a uniform distribution of 100 different results, as desired.