A long battery life is a boon for any product, obviously, but for a device like this it's extremely helpful. No-one wants to be messing around with Fido's collar every few days, and sheer bad luck dictates they'll manage to escape when it's on charge. Fi's collar uses AT&T's LTE-M low power network to keep going as long as it does. It's also got a useful lost dog mode, which tells owners and dog walkers straight away if the dog busts out of its permitted area. This comes with a remotely-activated collar light, too, so the dog will be easier to spot at night.
Like Whistle, Fi's collar requires a subscription to access all of its features, although it's a bit cheaper than its main competitor: between $1.59 and $1.89 per week, compared to Whistle's starting price of $6.95 per month. (The device itself, however, is a little pricier -- $149 compared to Whistle's $100). Plus, it looks good. Unlike some other pet tracking devices on the market, Fi's is sleeker and less obtrusive, so your dog will be as happy wearing it as you are knowing they're in safe hands. It's available now at tryfi.com.