Assuming you have obtained a clean "400in1.nes" file, here is how to run it on modern devices:
The exterior is made of cheap, thin plastic that feels fragile. Buttons are often shallow and can become unresponsive if pressed too hard. 400in1 nes rom download new
The 400-in-1 NES Retro Handheld Go to product viewer dialog for this item. Assuming you have obtained a clean "400in1