I designed a portable pocket sized air pump for aquariums and for fishing to keep the water oxygenated for your catch or bait fish. This uses a very small and quiet air pump that runs off of 2 AA bateries. I used a 3v air pumpAmazon.com : Hxchen 2Pcs DC 3V 12A Mini Air Water Pump Motor for Aquarium Tank Oxygen Circulate : Pet Supplies, a latching micro switchmxuteuk 50pcs Black Latching Mini ON/Off Switch Self-Lock Micro Push Button Switch DC 30V 1A for Light Lamp Wall Outlet DIY SMD Flashlight Type BK-1208: Amazon.com: Industrial & Scientific, and a AA battery tray/holder Amazon.com: WAYLLSHINE 12Pcs 2 x 1.5V AA Battery Holder Case Box, 2 AA Battery Holder with Wire Leads : Electronics. To build this just solder from the negative of battery to negative terminal of the air pump. positive of battery to one side of switch and another piece of wire from the unused terminal of the switch to the positive of the pump. Test the switch to verify it turns on and off then install the components. i installed the battery tray with double sided tape but there are holes if you have a m3 scew small enough. Next install the pump into the pass through hole at an angle then push down and fwd into final placement. To create a good seal i used superglue around the pump outlet and the case(hot glue would also work. Finally install the button and then the switch into place. Test a final time then attach 4mm ID tubing to outlet port and then to an air stone. There are also 2 m3x4x4 heat set insert holes for attaching the belt clip if needed. i printed it in petg but pla should be fine just keep out of direct sunlight of heat. I did test this and was able to run it for 6+ hours.