The first magnetic tape cassette. It was designed to address the difficulty of loading and threading tape, which hindered mass adop­tion. The shell could hold two standard 7 in. reels of ¼ in. tape. It required a specially designed machine, the Lowe Optaphon 51WA, although the Optaphon could also play standard reels without the shell. It was allegedly designed to make it easier for women to use tape, with the tagline "What women want…" used in advertising (unconfirmed, but plausible).