Amazon.com: NNL DBTB0428B2G 40mm Powerful Cooling Fan for AVC 4028 12V 1A High Speed Server Fans 40 * 40 * 28mm Dual Ball Bearing 4-Wire 4Pin PWM : מוצרי חשמל
Amazon.com: 40mm Cooling Fan 500-12000rpm Ball Bearing 4cm AFB0412SHB 40X40X15mm 12V Brushless Miner Cooler Pwm Fan 4 Pin : מוצרי חשמל
Source Mini cooling fan 12v 40x40 40mm 4020 dc cooler fan on m.alibaba.com
Gdstime 40MM 3D Printer Accessories Radiator DC 24V 40x40x10MM Centrifugal Turbine Blower Fan 4010 Radial Exaust Cooling Fan - AliExpress