This is a Sharp ZQ-770 pocket organiser, or if you’re in the US I think they were marketed as the Sharp ‘Wizard OZ series’. I have no idea how many people will actually be familiar with this device. But I owned one of these for many years and thought it was great. It was around before Tablets, iPhones or even touchscreen PDAs. For £70 (at least that’s what I paid) you could get a mini computer that ran off 2AA batteries.