The Decoder Buddy Mini was developed to fit into smaller steam and diesel applications.  There has also been interest in HOn3 and S-Gauge applications.
 
The mother board includes; 
• One 21 Pin Decoder receptacle
• On-board 1KΩ resistors.
• Two pairs of track input pads
• One pair of motor input pads
• One set of stay alive pads (U+, GND and if necessary a third control wire ),
• One pair of speaker pads
 
NOT INTENDED FOR USE IN A DC SYSTEM.
 
Dimensions:
35mm Long x 16.5mm Wide
Seated decoder height varies from around 6.5mm High (WOW) to 8.5mm High (Soundtraxx).