G28243 - Horizonal Mini Submersible 6VDC Water Pump 

theelectronicg...
Mini submersible 6VDC water pump 1.6 liters per minute flow rate. Outlet port is about 0.29" diameter. Has 8" long waterproof power cable. Size of pump about 1.8" long x 1" dia. excluding output port. Brand new.
Note: I did have this pump running on 2V which is what the first clip of the video is showing. Then I connected it to a 9V battery and it really started to spray.
This pump would be perfect for a small DYI stone waterfall with a 3V adapter.