Review on Rechargeable AQQA Aquarium Air Pump: Portable Oxygen Pump for Fresh & Saltwater Tanks - Ideal for 1-100 Gallon Tanks. by Kim Cockrum

I use KULIFE rechargeable pumps and they have been great. I ran out of power supplies so thought I would buy this more expensive one which has another one with more power. The block arrived dead. After more than 12 hours (overnight) connected to the network, the device does not turn on. The LEDs and button do not work and the device vibrates intermittently. I have attached photos of this block as received. Not sure if it's used or not but there are scratches just above the INT mark and some grains of sand on it. Also notice the "KD" stamp on the metal clip. Looks like someone hand-drawn it, but I'm not sure. They asked to replace the block, they should bring it tomorrow. The interchangeable block also has a stamp. Now it works perfectly. The noise level is as expected and the battery works as expected.