Nano Pets
in 2006, Nano Pets were in stores again but not in the original shells, These re-issue Nanos had original guts of Nano Baby, Kitty and Puppy but were in the second generation shells at the bottom of this page.
Some of these reisses were of questionable quality. I heard many complaints that the screens are scratched or there is glue used.
It seems that the company just used their left over parts and started production after the new Tamagotchis came out.
Of course, most of these new Nanos were just fine. Just look them over carefully when you do buy one.
These are Generation2 Nanos.
There is a Teddy, Double (cat and dog in one), horse, turtle and bunny.
These are much harder to come by than generation 1 Nanos.
The graphics are very basic and the game is hard to learn, but once you've got that down these are pretty easy to take care of.
There are a lot of Nano clones. Here's just one example.
Same graphics, animations, food, menus, every thing!
The programing might have been a little different.
I treated them the same, but the clone evolved faster than the original.
Nanos are one of my favorites.
They are easy to take care of, have two games that are easy and have two food choices.
The buttons also respond quickly, always a great feature.

I have heard that Nano Baby's lifespan is 3 years.
One-quarter year per actual day (12 days)
Then Nano Baby "Joins the Happy Family" and you start a new game. Iv'e not ever gotten quite as far as 12 days so I'll have to believe what I've heard for now.

I had my Kitty clone going for 38 days! I really liked it It even changed after 25 days.
One of the most satisfying pets ever.