Check the listing for details. Viglen Sideways ROM cartridge System & for Acorn BBC Micro. Made in United Kingdom. Listed at 86.47 USD. Plugs into an Acorn BBC Micro ROM socket and then the cartridge holder clips into the expansion slot ("ash tray") on the left of the keyboard to allow easy addition and removal of ROMs without opening the computer or risking damage to the ROM or socket. Includes a ROM cartridge with more available here: https://www.ebay.co.uk/itm/124000525010 CJE Micro‘s have the world's widest range of Raspberry Pi/RISC OS & Acorn accessories including many from third parties, most of which are famously normally 'In Stock'. Established in 1981, we have always specialised in hobby computing and have gained a reputation for a broad knowledge with high quality pre- and post-sales service. CJE have, over the years, developed many of our own products for Acorn/RISC OS & Raspberry Pi computers. From the first.