Edited from an ebay listing:
First introduced in 1979 and used by
guitar greats like Randy Rhoads and Eddie Van Halen the M-117 Flanger
is widely regarded as one of — if not THE — best Flanger pedal of all
time. The LED-less design indicates a manufacture date of 1979 after the
company was bought out but before their original stock of PC boards was
exhausted.
