Combination DVD/VCR units rarely offered S-VHS format standard, only VHS. They are often part of a VCR or digital video recorder (DVR, PVR). The user still needs to program the VCR or DVD recorder. VCR/DVD combination units are made by Funai. Philips unveiled the first-ever home VCR, the N1500 videocassette recorder. The optional rear-seat video entertainment system offered a choice of VCR or DVD player. By 1987, VHS accounted for 90% of the VCR market in the United States. In 1977, Sony issued the first long-play Betamax VCR, the SL-8200. Philips released the first Video 2000 VCR, the VR2020, in the United Kingdom in 1979. At the top of the stairs was a stack of stereo equipment atop a VCR. Most camcorders produced in the 20th century also feature an integrated VCR. VC cassettes were originally developed for standard VCR. VCR later evolved into a related format known as VCR-LP. This type of radiation (VCR) is used to generate high-power microwaves. The changes to the PAL VCR are minor thanks to the existing VCR recording formats.