One of the most reliable power banks I've tested can even inflate car tires (and get 50% off in this Black Friday deal)

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What's the deal?

The AstroAI L4 is available from Amazon for $40, which is 50% off the regular price.

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ZDNET's key takeaways

The AstroAI L4 is available from Amazon for $80.It's portable, has an excellent runtime, and is very powerful and easy to use.The supplied hose is a bit on the short side, and there is no way to deflate overinflated tires.

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I never really knew how much I needed a portable air compressor until I got my first one. I'd been using either one that connects direct to an AC outlet, or a 12V unit that would plug into the car's auxiliary power system. It turns out that building a powerful air pump into a power bank is absolute genius.

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The AstroAI L4 is perfect whether you roll on four wheels or two.

AstroAI L4 tech specs

Max Pressure: 150PSIPower Capacity: 6,600mAh, offering up to 40 minutes of air pumpingAir Pressure Units: PSI, KPA, BAR, KG/CM²Auto Stop: YesCharging Input: USB Type-CPower Bank Output: USB-AAdjustable Preset Modes: Car/Motorcycle/Bike/Ball/CustomLED flashlight: Yes, white and redAccessories: Nozzle adapters Adrian Kingsley-Hughes/ZDNET

Contained in a unit measuring 6.49 x 2.75 x 1.96 inches and weighing 1.1 pounds is a power bank, air pump, and flashlight. This is the perfect combination for a device you would store in the glove box of a car or a backpack when you're out riding a bike or a motorcycle. When a minor emergency hits, you're ready.

The 6,600mAh battery capacity delivers enough power to top up an average car tire (195/65 R15) from 30PSI to 36PSI in under a minute, and it has enough longevity to refill up to a dozen of them on a single charge.

The air pump has four preprogrammed modes for inflating different items -- car tires, motorcycle tires, bike tires, and balls -- along with a custom mode that you can preset to a specific pressure range.

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The user interface of the compressor is clear and straightforward. The display is large and easy to read in daylight or at night, and the buttons are easy to understand -- the last thing you want to be doing when you're dealing with a tire issue is having to find a manual to decipher your air compressor.

The unit is supplied with a snap-on quick connector that is quicker, easier, and less fuss to use for car tires than the type that screw in place. It also comes with a set of adapters and accessories for inflating bike tires and balls.

Adrian Kingsley-Hughes/ZDNET

The air compressor features a USB-A output, so you can use the unit as a power bank, and a dual-color LED light for nighttime emergencies. You use the USB-C port to charge the unit.

Adrian Kingsley-Hughes/ZDNET

It's not perfect, though. It's close, but there are a couple of things I'd like to see added to a future version.

First, the hose is a little bit on the short side, which means you have to crouch down by your car to inflate tires. Something a bit longer than the 7.5-inch hose would make life much easier, but would also add to the bulk and weight of the unit.

Adrian Kingsley-Hughes/ZDNET

There's also no automatic way to discharge air from overinflated tires, so if you come across ones with too much air in them, the air has to be discharged manually by pressing the valve stem.

ZDNET's buying advice

The AstroAI L4 is the perfect tool for keeping in your glove box when you're on four wheels, and in your backpack when you're on two wheels. It's a quick and easy way to keep your tires properly inflated, saving money and making your journeys safer. The addition of a power bank feature and LED flashlight gives this bit of kit a lot of flexibility.

With a regular price of $80, this is a competitively-priced portable air compressor, and for me a must-have in the trunk.