Review on 🌬️ AC Infinity MULTIFAN S3, Quiet 120mm USB Fan for UL-Certified Cooling of Receivers, DVRs, Playstations, Xbox Consoles, and Computer Cabinets by Matt Patnaik

In June 2017 I bought a MULTIFAN S3. I wanted the external fan to be very quiet, have a speed controller, have feet or pads to dampen vibration, and be USB powered. It should be used for cooling Asus RT-AC56U/RT-AC56R vertical/vertical router. The average temperature of these routers with 2.4GHz and 5GHz radios enabled tends to be quite high (typically 90°C, especially in summer). I also didn't want to void my router's warranty by modifying it to support a fan (not to mention small fans, which due to their size tend to be very fast, so noisy - no thanks!). MULTIFAN S3 did just that. what I wanted. At medium speed, it's almost inaudible at 4 feet away. At medium speed, I lowered the temperature by about 10C just by blowing air off the side of the router. The screenshot I've attached shows before and after; earlier the temperature reached 75°C. With the MULTIFAN S3 installed, peak values reach 65 °C. Great for low frequency, purely external cooling! I used this setup for about 9 months until one day I started hearing a very fast and random "rattling" from somewhere near my network devices (all fanless except the MULTIFAN S3). This noise became more regular over a few days so I was able to trace the source: of course it was the MULTIFAN S3. Most likely the dual ball bearings have gradually become loose (moved too much in their path/sleeve) or perhaps the bearing grease has 'thickened', both of which can occur with prolonged use. I turned off MULTIFAN S3 earlier this week. where summer temperatures started to rise again. Within an hour of reconnecting the fan, the "rattle" and "click" returned no matter what speed the fan was set to. Damn. I don't think I got the lemon as it has been working fine for many months. This problem with ball bearing fans is common even with high-end PC case fans. This is one of the reasons why I prefer Noctua oil bearing (SSO/SSO2) fans, but Noctua doesn't make products like MULTIFAN S3 without 3rd party adapters. Fan, MULTIFAN S3 *does not provide a convenient way to repair, replace or re-lubricate the bearings due to the very strong plastic or aluminum company logo on the central axis on both sides of the fan. And even if it weren't, many of these types of fans on the market have sealed plastic cases so you still can't access them, forcing you to buy a replacement. Overall I give this product 4/5 stars because it definitely works. everything advertised and AC Infinity deserves credit for their product. Just watch out for storage issues.