See Part I.
Actually, this part should be Part I, because this is how the relationships between Nana and Kaoru began (see “Nana to Kaoru”, the self-bondage episode).
Out of curiosity Nana put on this leather one-piece suit and accidentally locked it, but there was no key, and Nana had to go to Kaoru. Yes, lockable clothes can be fun ;-)
The size of this Nana is approximately 10 inches and she can be bought here on eBay.