The VPM2 is a replacement for the now unavailable venerable VPM. At 12mm dia x 3.4mm thick, it's smaller than the original, and has presoldered leads!
The original VPM was a wonderful motor, so when it went out of production, we just had to find a replacement for it.
At 12mm dia x 3.4mm thick (1/2"dia. x 0.134"), it's a bit smaller, but still packs a wallop by giving 1G vibration at 12,000rpm from 3V, drawing less than 80mA.
Did we mention that it also comes with a pre-mounted sticky-tape strip on the backside? Makes it really easy to attach to your latest vibebot!