Sony's Reon Pocket Pro Plus reached 20°C on a reviewer's thermometer and eased London's heatwave commutes

At a glance

Best for: commuting through a heatwave.

Skip it if: you wear tight tops or a tie, or expect it to cancel humidity or the sun.

Reviewers agree: humid air is where it meets limits.

They split on: how much relief the plate delivers.

London reached 100.6°F in August 2026, and Engadget's Mat Smith got through several heatwaves with Sony's Reon Pocket Pro Plus, a cooler worn under your clothes against the top of your spine. His 27 August review calls it more effective at cooling the body than he'd expected. Expert Reviews' Jonathan Bray, commuting on the Central Line in the UK's hottest May week on record, put a Fluke infrared thermometer on its plate and read 20°C at the top setting, the surface temperature Sony targets, though only in short bursts.[1] [2] [3]

A Peltier element chills a stainless-steel plate that touches skin just below the base of the neck, where Bray says blood vessels run close to the surface and carry the cooled blood onward. HardwareZone's Cheryl Tan stresses that it isn't an air conditioner, since its fans only vent the unit's own heat. Sony's Thai store lists two thermo modules that alternate in intensity.[1] [4] [2] [5] [3]

It heats, too. In warm mode Bray's thermometer saw the plate reach 32°C, which he found too hot beyond level one, while Tom's Guide's Ashley Thieme, who runs cold, felt warmth spread through her body within seconds. Trusted Reviews says Sony quotes 5.5 hours at the top cooling level; Reece Bithrey got six to six and a half hours, Bray more than six, and Smith four to five on peak heatwave days. Bray and Bithrey each needed about three hours to charge.[2] [4] [6] [1]

Testers split on how much relief the plate delivers. Bray says it won't cancel humidity or the sun, though he felt far more comfortable with hydration and a small hand fan alongside. Bithrey, who rode the Piccadilly line with it, found the effect subtle next to a fan in the face yet noticeable once it was off. After a month with two models before her 9 July review, Tan says neck fans such as Torras's Coolify can cool more noticeably but are bulky and loud, and she found the Reon weaker in post-storm humidity. Tan and Smith both reported condensation.[2] [6] [5] [1]

What the plate does for core temperature is a separate question, and a Japanese crossover trial of a different Peltier neck cooler offers a clue. In the Descente Sports Science report, eight healthy men cycled for 45 minutes in hot conditions, once with the cooler and once drinking ice slurry. Neck skin temperature fell from the fifth minute and thermal sensation improved for about 20 minutes. But rectal temperature stayed elevated at minute 40, so the authors rated the effect on deep body temperature as limited.[7]

Fit is the practical check. Bray puts the unit at about 26mm off the back, which makes tight tops or a tie awkward, and Smith needed the longer adjustable vent under collars. Smith found Sony's temperature tag made no tangible difference, while Thieme relied on it for Smart Mode. Humid air is where Bray and Tan met limits, so judge it on the commute you dread most, in your usual shirt, with the top level on and a hand fan in reach.[2] [1] [4]