The LDP-3216S is a single colour 32 pixel by 16 pixel LED matrix display. The module is based on the TLC5920 from TI which allows all those LEDs to be controlled with only 8 microcontroller I/O lines.  Pixels can show as black (that is, completely unlit), or gorgeous blue.  Of course, it uses a standard HUB08 connection, so you can use the PLT-1001 or PLT-2001 driver boards to control it.

This display is tiny! The LED module itself is only 20mm, giving you great resolution in a small space.  Pixels are 1.9mm in diameter and are spaced 2.5mm apart.

These panels can be daisy chained horizontally to create a longer message display board.