This is the programming card for the HobbyWing pentium speed controllers. It's easy to use and very inexpensive which makes it a great addition to your RC electronics. It's extremely light and no bigger then a credit card so it's fits just about anywhere. It's super simple to program as well, simply connect the ESC's receiver wire to the card, hook up the motor, and plug in your battery. LEDs will light up on the card, it's pretty straight froward after that. Instructions come with the card to help you set it up if you get stuck.