For decades, the Zippo bottom stamp has marked the authenticity of every genuine Zippo lighter. The simple system of dots and slashes, initiated to aid identification of lighters coming back to Zippo for repair, was later replaced by letters and Roman numerals, and still later by letters and digits signigying the month and year of manufacture. Now Zippo is turning the whoe system upside down...literally. Bottomz Up displays the traditional Zippo stamp not only on the bottom, but also on the top of the high polish chrome lighter. The conventional date codem showing month and year of manufature, is stamped on the canned-style bottom, while the canned-style lid is branded with the year of manufacture and the symbol identifying it as Bottomz Up. Fits into standard Zippo display.