A transistor radio is a small portable radio receiver using transistor-based circuitry. Following their development in 1954 they became the most popular electronic communication device in history, with billions manufactured during the 1960s and 1970s. Their pocket size sparked a change in popular music listening habits, for the first time allowing people to listen to music anywhere they went. In the 1970s their popularity declined as other portable media players such as boom boxes and portable cassette players took over.