This self-inking rubber stamp will make it a snap for you to prepare Free Matter packages for mailing. Just position the stamp at the top-right corner of your envelope or package, with the indented part of the stamp facing away from you, and press down. Every bit as easy as sticking on a regular postage stamp, you'll instantly have a professional-looking two-line postmark saying FREE MATTER FOR THE BLIND in crisp, clear blue ink. What's more, the stamp is good for literally thousands of impressions before you have to refill the ink - which means you'll be able to ship an awful lot of Braille letters and Free Matter packages before your stamp needs any attention whatsoever!
(From the Writing Braille shelf.)