I just wish they would stop making the "140mm frame with 120mm mounting holes" fans. There are so many scenario's where you're borked because of it.
Why? A lot of good CPU coolers have 120mm mounts, and even a lot of cases have 120mm mounts, but on perforated/grill surfaces, so a 140mm fan that fits the mount actually can give much better airflow.
The Prolimatech Ultra Sleek Vortex 14's are great as replacement CPU cooler fans, or for use with heatsink only coolers that have fan mounts. With 15mm height you can easily fit them in more restrictive space, or even fit two on a cooler with two fan mounts, but poor clearance (either from the motherboard, height clearance or both). They also make great case-fans as the 1cm saved means less obstruction in smaller cases, or even in bigger cases, just having more free space usually makes working with them so much easier.
Of course it helps that they're not bad fans either; the airflow and static pressure are pretty impressive for a 15mm thick fan, especially given the relatively low rpm and very low noise.
This static booster does seem very niche though; I mean, you're making a fan, whose main benefit is its thinness, thicker. A thicker fan's frame should improve air direction anyway, and will cost you a whole lot less (the Ultra Sleek Vortex 14 is already quite pricey). To me the main benefit is that this fan can fit in loads of tight spaces, include places where you might not normally mount a fan, such as in a gap between an inner and out chassis; I'm currently building a system with a 2cm gap between the chassis proper and its plastic outer case, and this fan fits nicely in there, freeing up a full 2.5cm of internal space in total as a result.
