The Wordlock enables the use of letters and words as combinations that can be set and re-set. Word and letter combinations are easier to remember and offer an advantage over numerical combinations that can be forgotten or keys that can be lost. Wordlock uses patented algorithms to create the best mix of vowels and consonants, maximizing the number of four-letter words that can be created on Wordlock letter dials. You choose one from up to 10,000 different letter combinations. The locks are TSA-accepted and Travel Sentry approved, allowing airport security to inspect luggage without the use of bolt cutters. Get one for around $10.