Forget colourful cases or headphones, the latest accessory for your phone is...another phone.

A San Jose-based firm has designed a mini handset that attaches to current smartphones, using a specially-designed case.

Although doubling up the number of gadgets you have may seem a little pointless, or extravagant, the manufacturers claim it can be particularly useful if the battery on your main device dies, for example.

Scroll down for video

Talkase (pictured), from San Jose-based Wirelessme, costs $69 (£42). This package includes the phone, case, charger and micro USB cable. The device works as a standalone feature phone, and connects to smart devices via Bluetooth so it can be used as a backup phone, or used when travelling

Called Talkase, the $69 (£42) device has 100 hours of standby time and 2.5 hours of talk time, works as a standalone device, and connects to other devices via Bluetooth.

This means it is also an alternative for parents who don’t want their children to have a smartphone, or as a phone designed for travelling.

THE TALKASE SPECIFICATIONS The Talkase package costs $69 (£42), which includes the Talkase phone, the iPhone protection case, charger, micro USB cable and silicon case The $69 (£42) Talkase can be used to make and receive phone calls. It has 100 hours of standby time, works as a standalone device, and connects to other devices via Bluetooth. It is 0.2-inch (5.5mm) thick, the size of an average credit card, and fits inside a case that snaps on to an existing smartphone. Devices will be shipped in December, available in white, black, blue and orange. Advertisement

For the price, buyers additionally get a case, charger and micro USB cable.

Talkase was designed by WirelessMe, which is seeking $60,000 (£37,200) on Kickstarter to fund production of the device.

'Burdened by larger-than-life smartphones that resemble tablets more than cell phones?

'It's time for a Talkase,' explained the Kickstarter campaign.

'And forget carrying around a charger, worrying that your phone might run out of battery. Talkase has you covered.

'Tired of carrying around two phones while traveling?

'You guessed it, Talkase can help you with that, too.'

The campaign runs until 20 November and has currently raised more than $25,500 (£15,800) towards its goal.

Because Talkase uses Bluetooth, it syncs with any enabled device meaning contact lists, for example, are automatically synced.

Talkase supports quad-band frequency, meaning it can make and receive calls when any micro-SIM is put into the device.

It can also be used to send and receive text messages.

The miniature handset is 0.2-inch (5.5mm) thick, and is the size of an average credit card.

Talkase is 0.2-inch (5.5mm) thick, is the size of an average credit card and was designed in conjunction with a patented case that snaps on to an existing smartphone (pictured). If the campaign achieves its funding goal on Kickstarter, devices will be shipped in December in four available colours – white, black, blue and orange.

It was designed in conjunction with a patented case that snaps on to an existing smartphone.

If the campaign achieves its funding goal, devices will be shipped in December in four available colours – white, black, blue and orange.

So far, the case is only available for select iPhone and Samsung models, but WirelessMe said it is working on cases for other devices.

And because of its dimensions, the case can also be used to store credit cards.