It's a small USB to TTL serial tool, using the PL2303 chip.
You can use it to connect some serial device to your PC via USB port, an avr, an msp430 or an stm32 for example.
It's very cheap compared to the ft232 alternative and works very well, up to more than 1mbit/s.
It is a good plastic box for Raspberry Pi, which can protect it with one of these snazzy plastic enclosures?. These cases protect the Raspberry Pi from things like rogue wires that might short it out while still allowing full access to the board! Simply snap the RPi into the bottom half of the enclosure, then snap the two sides together.
This is a T-Cobbler breakout kit used for extending the GPIO interface on Raspberry Pi B+,2 or 3 to breadboard. It helps you to make the connections between Raspberry Pi B+/2/3 breadboard become simple.