Microwave oven
Japan's Sharp Corporation began manufacturing microwave ovens in 1961. Between 1964 and 1966, Sharp introduced the first microwave oven with a turntable, a feature that promotes convenient even heating of food. In 1965, Raytheon acquired Amana. In 1967, they introduced the first popular home model, the countertop Radarange, at a price of US$495 ($ in dollars).
Sandwich
It has been suggested that UK's first pre-made packaged sandwiches were sold by Marks & Spencer in 1980. As they proved wildly popular, a small experiment involving five stores rapidly grew to cover more than one hundred stores. Within a year, the store was looking for ways to manufacture sandwiches at an industrial scale.
However, the first pre-packed sandwiches date from well before this. British Home Stores sold pre-packed sandwiches in the 1960s (see the Radio Times 3 November 2018 p.167), and earlier even than that, Marks and Spencer (Brighton branch) began selling them in the 1950s, and then in the 1960s in the Oxford Street branch, London. (See the Radio Times 10 November 2018 p.160)