In 1968, a chemist in the United States, developed a "low-tack", reusable, pressure sensitive adhesive. In 1974, a colleague of his, who had attended one of the chemists seminars, came up with the idea of using the adhesive to anchor his bookmark in his hymn book. 3M launched the product in stores in 1977 in four cities under the name "Press 'N Peel". On April 6, 1980, the product debuted in US stores as "Post-It Notes". In 1981, Post-its were launched in Canada and Europe.