Blinkie Tamagotchi Electronic Pet - Keyring - Great Fun - Tested & Working
Uses 4 x AAA batteries which are NOT included.
Tested and working as you can see from the pictures.
It's worth mentioning that when you insert the batteries make sure the toy lights up and starts to work before you screw down the battery cover as the batteries have to be set right and you don't want to have to unscrew the cover again to adjust.
You'll need a precision screwdriver for the battery cover but these sets are now widely available in £1.00 shops
No instructions I'm afraid, other than the sticker on the base. There are various forums on the internet for info though such as tematalk
Battery compartment is nice and clean.