You should always carry your towel with you, whether you’re hitchhiking across the galaxy or just watching TV at home. This one fits right in your pocket, your wallet, wherever.
Towels are made of soft terrycloth. Due to availability, sizes vary slightly, but they are all approximately 2.5 inches by 4 inches.
The Guide has this to say about towels:
“A towel, it says, is about the most massively useful thing an interstellar hitchhiker can have. Partly it has great practical value. You can wrap it around you for warmth as you bound across the cold moons of Jaglan Beta; you can lie on it on the brilliant marble-sanded beaches of Santraginus V, inhaling the heady sea vapors; you can sleep under it beneath the stars which shine so redly on the desert world of Kakrafoon; use it to sail a miniraft down the slow heavy River Moth; wet it for use in hand-to-hand-combat; wrap it round your head to ward off noxious fumes or avoid the gaze of the Ravenous Bugblatter Beast of Traal (such a mind-boggingly stupid animal, it assumes that if you can’t see it, it can’t see you); you can wave your towel in emergencies as a distress signal, and of course dry yourself off with it if it still seems to be clean enough.”
Okay, this towel might be a bit too small to do all of those things, but at the very least, it will remind you to not panic.
Comes in a many colors and patterns: solid color (yellow, green, pink, blue), stripes (yellow/green, pink/blue, blue/green), or dotted (orange/yellow/green, blue/green, pink/orange).