This is an adapter developed to use later Apple II joysticks with earlier Apple II and IIplus.
It's easy to use, just insert the plug adapter into the 14Pin IC Plug and secure the db9 adapter to the back panel with two screws. The cable used for this is designed to prevent incorrect insertion, so you can use it with confidence.
 
*Well known issue: In the case of RFI motherboards, the Q3 transistor head contacts the board. There are individual differences in the mounting angle and height of the transistor, so adjustments may be necessary. This can be avoided by slightly bending the transistor feet, or by replacing the board feet where the blade feet currently sit with machine pin headers(Machine pin headers are long). Please note.

Fully assembled set
/18 USD
 
Bare PCB
/6 USD
*In the case of BarePCB, you need to prepare all the parts yourself. Also, since the PCBs are firmly connected, they can be separated using a band saw or a scroll saw. The reason for the connection is to manufacture cheaply. This is a process to prevent it from being considered as a multifaceted or heterogeneous facet.