12V Fan to USB Adapter with Converter - Black - Male to Female - 400mA Max - 25cm Cable - Compatible with 12V Fans with Molex 3-pin Connector

It us what it is. I am using it to power a 120mm fan on my small comms cabinet. Taking power from the usb port on the back of my sky box. It comes with a resistor to step down the voltage to enable the fan to run slower. I am using this. Make sure that the fan you are using is capable at running at the lower voltage. Some will not and some may require a push with your fingers to get going

does what it says but extremely expensive

FAN2USB - 12V USB fan - Converting Adapter Brilliant and simple adapter to connect to a 3 pin 12v molex fan. Works fine with eather a USB 1A or 2.1A port. Currently running a 15 year old 80mm CPU cooling fan to keep a battery charger cool. Deffinatly well worth the cost. Update1: my first unit died after 18 months of hard use including a couple of trips to Belgium and was mainly used to quickly cool tea and to keep my radio gear cool. Update2: my second unit died after another year of hard use seems the resister overheated in the summer when using an Intel Cooler Master A46002-002 (Sanyo Denki 109R0612G4031) which is an amaizing fan. Update3: my most recent unit which was delivered yesterday didn't work full stop no output what so ever and the plus pin (pin 1) was bent so I did the next best thing I spliced an old cig socket cable onto a 4 pin Noctua 3 fan 30W controller turns out with 12V input you can't manually control fan RPM on the output so I hooked a 3 pin Gelid fan controller to the 4 pin out of the Noctua and job done I have full manual speed control currently cooling down my mid morning cup of tea using my trusty Intel fan so now the setup is a xiaomi 5000 MAh USB battery > USB to 12V step-up module with 5.5x2.1mm output > cig socket cable to 4 pin Noctua controller > 3 pin Gelid controller > Intel fan eventually I'll probably illimanate the Noctua controller and directly splice the Gelid to the cig cable but not seeing any voltage drop what so ever still getting exactly 12.0V on the output with fan at full throttle. These units are good for your bog standard case fan but could potentially fail under warm conditions if using higher current fans still within the spec of this cables 400 MA output and assuming you don't end up with a dud.

I was a bit 50/50 on the price bit it's defiantly worth it. High quality for my 12v fan. Would highly recommend.

Works as expected I am now using a molex fan as a usb fan.

Just what I needed