Only giving 3 stars because one of the two cables was defective and wouldn't allow simultaneous button presses.
Hi there.
Thank you for taking the time to leave a review. We apologize for the inconvenience caused by the defective cable. Please communicate with us for an exchange out of charge.
It runs smoothly on my GBA and SP. With NES and Game Boy emulation on my Picoboot GameCube I can switch the SD between the two consoles and play like a Switch with the same game files.