You can use it to repair broken slot Famicom or use it to make Catridge Reader.

You can use it to make Catridge Reader. Or use for development. It is not for real Game Boy. It can use for GB/GBC/GBA Cartridge.

You can use it to repair broken slot Genesis/MegaDrive or use it to make Catridge Reader. MD Pro programmer use it to make.

You can use it to repair broken slot Japan Mark III or use it to make Catridge Reader. Mark III converter for MD use it to make.

It is not replacement parts for NES. So, you can not use it to replace damaged NES Slot. You only can use it to make something like Cart Reader.