Yes, by popular demand we can now supply a spherical drain plug!
It is cool and can plug the drain socket in direction.
It should fit your 40A type drain fitting.
The ball is in durable chemical rubber: after many years it may shrink slightly but will not ovalize.
The chain and ring are in stainless steel.
(as of 3.1.2014 there was a price increase from the maker.)
The price is:
6,500 JPY as an option for a new tub
or
7,900 JPY + EMS shipping fee if you only want to purchase the plug.
Kobe Kazamidori chapter
japan@bartokdesign.com
COMMENTS~