SilverWook said:

It appears to be an Atari 2600 compatible joystick. Atari wasn't as strict as Nintentdo about third party products, so there were a lot of companies making all sorts of controllers. The fringe benefit was competitors such as Colecovision could use the same sticks too.

The 9-pin 'D' connector layout became something of a de-facto standard joystick port in the 8-bit console/home computer era (and carried through to early 16-bit machines too). The same joysticks could be used with Atari (2600 console and 8-bit machine such as 400, 800, XL and XE series), Commodore C64, Amstrad CPC, Sinclair ZX Spectrum, Atari ST and Amiga.