This is a Delta Electronics DC12V 0.35A 40x40x15mm 4-Pin DC Brushless Fan. Its model number is AFB0412SHB-8J73. If you are unhappy with one of our products, you can send it back as long as you follow these basic rules.
I got this to replace the extruder fan on a 3d printer. MAJOR improvement over the stock fan! The stock fan will just dangle if held by the cord and powered on. This fan will move 3-4 inches. It is quite a bit louder than the stock fan but the performance outweighs the increased noise.