9-zone heated puffer jacket, black, size 4XL

How the heating works

Thin carbon fibre heating wires are sewn into nine areas of the lining: two at the front by the pockets, one in the collar, and six across the back from the shoulders down to the waist. A short USB lead sits in an inside pocket. Plug it into a charged power bank, then hold the button on the chest for about two seconds to switch the heat on.

Press the button again to change the setting. The light in the button shows which one is on:

• Red: warm, 45 °C
• White: comfort, 35 °C
• Blue: energy saving, 25 °C

These temperatures are the supplier's figures for the heating pads, not for the air inside the jacket. With the heat off it is a padded hooded jacket with a synthetic outer and cotton filling. The supplier describes the hood as detachable with a zip, and the cuffs and hem as elasticated.

Size chart in cm (you are viewing 4XL)

"Laid flat" means measured straight across the front of the jacket from armpit to armpit. Double it for the full chest. The maker allows for 2 to 3 cm of difference, because the garments are measured by hand.

These jackets come up small. They are cut to Asian sizes. The maker says they run 1 to 2 sizes smaller than UK and European sizes, and buyer reviews of this jacket say 2 to 3 sizes. The easiest check: lay a jacket that fits you well flat, measure across the chest from armpit to armpit and pick the size with the same number or a little more. Leave room for a jumper underneath. Our size guide explains the measuring step by step.

Power bank and battery time

The power bank is not included. The jacket runs from any 5V USB power bank with a standard USB-A socket, which covers almost every power bank sold for phones. Our 10,000 mAh power bank fits the inside pocket.

The supplier quotes up to 8 to 12 hours of heat from a 10,000 mAh power bank. Expect less on the red setting and in hard frost, because lithium batteries give less power in the cold. Start on blue or white and only turn it up when you need to. Our guide how long does a heated jacket last? shows how to work out battery time for any power bank.

Washing and care

Always unplug and take out the power bank before washing, and tuck the USB lead into its pocket. The maker says the jacket can be washed by hand or in a machine. To protect the heating wires we recommend a gentle hand wash in lukewarm water, no wringing, and drying on a hanger away from radiators. Let it dry completely before you plug a power bank in again. More tips in how to wash heated clothing.