MM550

Psion Organiser was the brand name of a range of pocket computers developed by the British company Psion in the 1980s.] The Organiser I (launched in 1984) and Organiser II (launched in 1986) had a characteristic hard plastic sliding cover protecting a 6×6 keypad instead of a computer keyboard, with letters arranged alphabetically. 

My husband doesn't like to throw things out.  He must have known that it would have come in useful for my MM blip more that 40 years later. 
Thanks to 60plus for hosting.