it will be sufficient to plug it on kernal socket and it will work without piercing the case and WITHOUT EXTRA WIRES!
It can be PAL or NTSC.
How to handle switching between kernals?
The PLUS4 will boot-up with standard kernal (I prefer always that on standard boot-up the machine seem not modified....)
the kernal will swap each time you will press the reset push button (the original will become JDOS, or JDOS will become the original one),
but reset via software will have no effect.
Obviously it's designed to fit inside the PLUS 4 without cause problems at correct case closing.
NOTE: the price includes the $ 8 that will be paid as a copyright at the conclusion of the sale.
22€ (8$ royalty fees included) + eventual Paypal fees + shipping cost