The Tangerine Microtan 65 (sometimes abbreviated M65) was a 6502 based single board microcomputer, first sold in 1979, which could be expanded into, what was for its day, a comprehensive and powerful system. The design became the basis for what later became the ORIC ATMOS and later computers, which has similar keyboard addressing and tape I/O as in the Microtan 65. The Microtan 65 has a single step function that can be used for debugging at the hardware level. The computer was available as ready-built boards or as kits consisting of board and components requiring soldering together.