These compact Motors are high quality Swiss/German made, they are very powerful yet quiet, speed is around 28 rpm, on a battery box  at 12 volts. 32 rpm on a 12 v transformer,  55 rpm on a Hamant and Morgan clipper train transformer at full power, two mounting bolts in the base make a very easy and rigid fix to models. 
 
Includes 2 minature plugs and sockets
 
Size L 3" x W x 1.75" x 1.75, (75 mm x 46 mm x 46 mm)
 
Shaft size 10mm long x 4mm to take Meccano parts.
Motor can be slid forward in it's mounting in order to engage gears