An optional D-ring makes it easier to hang the ScrewMaster from a keyring

While there are many multitools that include a bit driver along with a lot of other tools, what if a driver is all you really need? That's where the tiny, compact ScrewMaster comes in - and it does also let you break car windows in emergencies.

Made by outdoor gear company Mr. Gadget, the ScrewMaster is currently the subject of a Kickstarter campaign.

It measures just 38 mm long by 14 mm wide (1.5 by 0.6 in), tips the scales at a claimed 22.8 g (0.8 oz), and is designed to be worn as a pendant on a chain, threaded onto a paracord lanyard, or attached to a keyring.

The device's polished-brass bit driver accommodates any third-party quarter-inch screwdriver bit, which is held in place by an integrated magnet. That said, a set of 10 system-specific bits is available as a $12 optional extra. It should be noted, however, that only one bit can be stored in the ScrewMaster (in its driver) at once.

When the tool isn't in use, a magnetically attached Grade-5 titanium end cap covers the bit. That cap simply gets pulled off once it's time to start screwing around.

A knurled titanium top cap is utilized to grip and twist the tool when it's in use. The very top piece, which contains the chain/lanyard/keyring hole, quickly screws into and out of a threaded hole in the top cap. This means the main device can be removed from the keyring, etc with little effort.

And yes, a hardened glass knub at the tip of the ScrewMaster can be used to break automobile windows, should the user find themselves trapped in a crashed car. As an added bonus, four slots arranged around the outside of the bit driver can accommodate an optional $60 set of glow-in-the-dark tritium vials - you know, for finding the device in the dark.

Assuming the ScrewMaster reaches production, a pledge of US$42 will get you one, along with a paracord lanyard. The planned retail price is $69.