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ThruNite T10 115 lumen Cree XP-G LED flashlight
The ThruNite T10 is a lot of light packed into a small space. The Cree XP-G LED is rated to last over 50,000 hours and can output anything from 0.09 lumens (which is very dim, described as "firefly" mode) to 115 lumens (which is dazzlingly bright).
A single AA battery can give you light for anything from 147 hours to 1.5 hours, depending on the brightness you choose.
Awesome light. I've carried one in my pocket for over a year and it's never failed me.
Link | Price: Around $18.
This is a Swiss Army Knife that fits into your wallet, and has a variety of tools ranging from a knife to a pair of really sharp scissors.
Link | Price: Around $25.
Fisher Space Pen
Probably the most reliable pen I've ever owned. Not only can I safely carry it around in my pocket without fear that it will leak, it's very reliable and will write on almost any surface, and at any angle.
Link | Price: Varies.
(Image: Fisher Space Pen Company)