advanced on the market for a portable video game unit at the time. The screen contributed to its high price and short battery life, however, which hurt its performance in the market. It also has a TV tuner adapter as well as a two-player link cable. LT The PC Engine LT is a model of the console in a laptop form, released on December 13, 1991, in Japan, retailing at ¥99,800. The LT does not require a television display (and does not have any AV output) as it has a built-in flip-up screen and speakers, just as a laptop would have, but, unlike the GT, the LT runs on a power supply. Its expensive price meant that few units were produced compared to other models. The LT has full expansion port capability, so the CD-ROM² unit is compatible with the LT the same way as it is with the original PC Engine and CoreGrafx. However, the LT requires an adapter to use the enhanced Super CD-ROM² unit. Duo NEC Home Electronics released the PC Engine Duo in Japan on September 21, 1991, which combined the PC Engine and Super CD-ROM² unit into a single console. The system can play HuCards, audio CDs, CD+Gs, standard CD-ROM² games and Super CD-ROM² games. The North American version, the TurboDuo, was launched in October 1992. Two updated variants were released in Japan: the PC Engine Duo-R on March 25, 1993, and the PC Engine Duo-RX on June 25, 1994. The changes were mostly cosmetic, but the RX included a new 6-button controller. Third-party models The PC-KD863G is a CRT monitor with built-in PC Engine console, released on September 27, 1988, in Japan for ¥138,000. Following NEC's PCs' naming scheme, the PC-KD863G was designed to eliminate the need to buy a separate television set and a console. It output its signals in RGB, so it was clearer at the time than the console which was still limited to RF and composite. However, it has no BUS expansion port, which made it incompatible with the CD-ROM² System and memory backup add-ons. The X1-Twin was the first licensed PC Engine-compatible hardware manufactured by a third-party company, released by Sharp in April 1989 for ¥99,800. It is a hybrid system that can run PC Engine games and X1 computer software. Pioneer Corporation's LaserActive supports an add-on module which allows the use of PC Engine games (HuCard, CD-ROM² and