Neck Warmer & Cooler, Neck-Hanging Cooling/Warming 2 Modes, necOn

Purchased used.
I bought it for commuting on foot, but while the cooling capacity alone was fine, it didn't seem suitable for outdoor use.
It might work as a warmer in winter, but I don't need a portable heater in winter, so I'm selling it.
It shows some signs of use, but it comes with all accessories, including the instruction manual.

Product Description
[Cooler Mode: 3 Levels Adjustable] The cooler mode offers rapid cooling with 3 temperature settings: Low/approx. 25°C, Medium/approx. 20°C, and High/approx. 15°C (*1). By directly applying the cooling plate to your neck, you'll experience a refreshing chill, like holding a cold canned drink to your neck, even on windless days or in the summer heat outdoors. You can switch between cooling and warming with a single button, so it can also be used to combat cold sensitivity by warming your neck even in rooms with strong air conditioning. It's also useful during the temperature fluctuations between day and night in summer. (*1 The surface temperature of the plate when worn may differ from the set temperatures. Depending on the ambient temperature and environment, the set temperature may not be reached.)
[Warmer Mode: 3 Levels Adjustable / Auto Shut-off Function] The convenient warmer mode for autumn and winter provides instant warmth with 3 temperature settings: Low/approx. 39°C, Medium/approx. 42°C, and High/approx. 45°C (*1). You can comfortably warm your neck in the cold winter at your preferred temperature, and the heat therapy can also help you relax. It features an auto shut-off function that turns off the power after about 10 seconds if the plate temperature reaches 45°C, providing peace of mind even when stored in a bag. (*1 The surface temperature of the plate when worn may differ from the set temperatures. Depending on the ambient temperature and environment, the set temperature may not be reached.)
[Built-in Battery for Use Anytime, Anywhere] With a built-in 2600mAh battery and a cordless design, there's no need for bulky external batteries. Approximately 3 hours of charging allows for about 2 hours of continuous operation in cooler mode and about 2-5 hours in warmer mode (*2). (*2 Operating time when worn in an environment with an ambient temperature of approximately 25°C.) You can charge it using the included USB cable from a PC or mobile battery. It can also operate while charging, making it useful in places without power outlets, such as outdoors.