It looks like a 'Fit Bit', but this wearable means you can go surfing without having to stash a key in a hiding place.
Is this the coolest car accessory to go on sale this year? There's just one catch: those who would use it most can probably least afford it.
There's now no need to hide your car key wrapped in a beach towel, in the toe of your shoe, or on top of a tyre while you go for a surf, bike ride or bush walk.
A weatherproof rubber wrist band — similar to a Fit Bit — has replaced the humble key on the new Jaguar SUV released in Australia today.
The device enables you to lock the original car key inside the vehicle.
Simply hold the wrist band near the 'J' on the Jaguar badge on the tailgate and it locks the car, James Bond-style.
The original key you've left behind is useless until the wristband you're wearing unlocks it.
Repeat the process to unlock it after you've finished surfing/skydiving/bush walking or whatever adventure sport takes your fancy.
If someone breaks into the car while you're gone, the original key you've left behind is useless until the wristband you're wearing unlocks it.
For now the technology is an exclusive option — costing an extra $640 — on the Jaguar F-Pace, which is priced from $75,000 to $120,000.
But although the device is patented by Jaguar, other brands are certain to follow, making it available on more affordable cars in years to come.
The wider availability of "sensor" keys, which unlock a car when you get in proximity to it — even when it is in your pocket, handbag or briefcase — has made it increasingly difficult to hide a key under a bumper or resting on a tyre.
The company expects to make the rubber wristband key available on more models if it proves popular with buyers.
That's because the car can easily be unlocked if a sensor key is nearby.
Jaguar engineers then came up with a wearable sensor key to solve the problem.
All the driver needs to do is tap the tailgate door switch to "wake up" the car, and then place the wristband near the 'J' on the Jaguar badge.
Jaguar says it is too early to say how many buyers will take up the 'Activity Key' option, as the new F-Pace — the first car in the world with this feature — has only just gone on sale.
But the company expects to make the rubber wristband key available on more models if it proves popular with buyers.
What's the coolest gadget you've seen on a car? Tell us what you think in the comments below.