First, I just recently received this charger. And so far, I am impressed. It is well built. And contrary to other reviews it absolutely DOES HAVE AN ON/OFF SWITCH. To repeat: This model has an ON/OFF SWITCH! However, there is some confusion because there seems to be three different models of this charger which are not clearly differentiated. One is a "base" model, another has allegator clips, and the third model (which I purchased) has the 3 prong onnector and is the most expensive. To make a long story as short as possible, I purchased a Pride Go-Go Sport 4-wheel mobility scooter about a year ago... Recently, the batteries failed and the factory-supplied charger seems to be the culprit. The charger, all plastic, no fan, no on/off switch seems to have failed its function of being a battery maintainer "float" charger and burned up the batteries. So I ordered this charger which appears to be much better built, has a cooling fan, and does have the on/off switch and is also a battery maintainer float charger. So, now that I have new batteries, I used the new charger to top off the new batteries. The charger worked flawlessly. And the LED lights that show the four stages of charging worked. So far, I am very pleased. The old factory-supplied so-called battery charger/maintainer took over 12 hours to show a "green" fully charged battery; this one showed fully charged in just 3 hours. Very happy so far! Only quibble is $50 is expensive!