The Pro Trinkets are like an Arduino Pro Mini but with more pins, FLASH, and RAM. The Pro Trinket has 18 GPIO, 2 extra analog inputs, 28K of flash, and 2K of RAM. The Trinkets have onboard USB bootloading support and feature a MicroUSB jack. Optiboot support has been added to program the Pro Trinket over USB or with an FTDI cable.
The Pro Trinket PCB measures 1.5x0.7x0.2" (without headers) with the same capability as an Arduino UNO. The Pro Trinket is programmable using the Arduino IDE and works with 99 percent of Arduino projects out of the box.