The Konami Q Famicom
Adaptor is an accessory converter that attaches to
the pins of the Famicom. It allows gamers to play
the special cartridges Konami and NHK made for the
Famicom.
It's unknown why Konami made their carts different
and why they required the use of this converter
instead of using the standard Famicom carts.

The box for the Konami Q Famicom Adaptor.

Konami and NHK collaborated to make the adaptor.
Konami's Q had a
least one, but likely a few more, games for it.
Space School is the only game known to exist for
the converter. The Space School cartridge is
square with a hole at the bottom where the pins of
the cart connect to the pins of the converter. The
unique shape of the Q cart does not allow it to be
directly inserted into the Famicom.

There weren't many games made for the adaptor.

Why did Konami made these carts different from
Famicom carts?
Konami Q is very rare
and usually sells for about $150.
Though it's unclear why Konami released such an
adaptor, it's would be a neat item to play around
with should you ever come across one.