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Compact square phone cooler with carbon-fibre texture, magnetic back, RGB LEDs and temperature display

shijianwy K21 Phone Cooler Cord Charging Version

SKU CH-8J2P-VVH5D

USB-powered semiconductor cooler with magnetic or clip attachment fits phones and tablets, drops temperature fast, runs at 25 dB and 9000 RPM, and weighs 63 g

  • Accessory categoryCord Charging Version
  • Measurements2.6 L × 2.6 W × 0.85 H inches
  • In the boxPhone cooler*1N
  • Cools phone in minutes using semiconductor refrigeration
  • Compatible with iPhone 12 13 14 15 16 via MagSafe
  • Lightweight 63g design reduces wrist strain during gaming
  • Real-time temperature display on LED screen
  • Quiet 25 dB operation at 9000 RPM fan speed

Phone Cooler for Gamers and Streamers

The shijianwy K21 attaches magnetically or with a clip to smartphones and tablets, drawing 5 V DC power through a 2-pin USB connector. It targets mobile gamers, live streamers and content creators who need their device to stay cool during extended sessions. The unit weighs 63 g and measures 2.6 by 2.6 by .85 inches, so it adds minimal bulk. Compatible models include iPhone 12 through 16 series, iPad Pro 12.9, 10.9 and 10.2, Samsung Galaxy S24 and S23 Ultra, Google Pixel 9, 8 and 7 Pro, plus Nintendo Switch and laptops.

Sustained Cooling Behaviour

Semiconductor refrigeration drops the contact surface to minus 15 °C within 30 seconds when ambient temperature is below 25 °C. A 9000 RPM fan moves air at a stated 25 dB noise level while an LED readout shows real-time temperature and the active refrigeration stage. Three adjustable stages let the user balance cooling intensity against acoustic comfort for long periods. The physical power switch provides instant on-off control without unplugging.

Upgrade from Passive or Clip-On Fans

This cooler replaces basic clip-on fans or passive heatsinks that rely only on airflow. The jump is worth it when a device throttles during heavy gaming, streaming or video calls and the user needs active sub-ambient cooling rather than simple air movement. Buyers who need a built-in battery for untethered use or who require cooling for devices without a USB power source nearby will not be served by this cord-powered version.

How it compares

Measured against everything we stock in Laptop Cooling Stands & Fans, at today’s prices. Recalculated every night.

Price $25.99
Pricier than about 60% of the 6,190 comparable items (median $20.99).

Specifications

Product
Brand nameShijianwy
Model nameK21
Part numberK21
Accessory categoryCord Charging Version
Size & build
Measurements2.6 L × 2.6 W × 0.85 H inches
In the box
In the boxPhone cooler*1N

Questions about this item

How loud is the 9000 RPM fan when it runs continuously?

The fan produces 25 decibels, so it stays quiet during long gaming or streaming sessions.

What power source do I need to run the K21 cooler?

A USB port or charger that delivers 5 V DC through a standard 2-pin connector powers the unit.

Will the magnetic attachment work with my iPhone 15 Pro Max case?

Yes, the cooler magnetically couples with MagSafe-compatible cases on the iPhone 15 Pro Max and other listed models.

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