Review on AQQA Aquarium Lithium Battery Air Pump - Multifunctional, Rechargeable, Energy-Saving, and Quiet Oxygen Pump with One/Dual Outlets, Air Stone, and 2600mAh Battery - Suitable for Indoors, Power Outages, and Fishing by Brittany Smith

I appreciate this product because it is very quiet. I thought I could hang it on the side of the tank because it has a clip, but I have an acrylic tank with no "lip" so that's not an option for me. However, it sits on top of the tank and I can barely hear it running, and the lower horsepower is enough for my 50-gallon tank. It has a decent run time on a battery, but I usually left my old pump plugged in. Disappointing with the cable length. Your outlet must be in close proximity to the tank or USB port. I'll try to see if I can get a longer one from the manufacturer or get specs for it to order elsewhere.