Business Card File - Holds 120 Cards

# See Porthos's office supplies here
This is a business card file that was found in storage. It is unused, but it has been left lying around, so there are some minor stains and it looks generally aged. According to the product description inside, the price at the time was ￥1,500, so I believe it is quite durable. Considering that consumption tax is not indicated and the Tokyo phone number has one less digit than it does now, it is likely over 35 years old.
I do not know how to open the rings of the file. It is possible they are stuck and will not open.
The dimensions are:
Outer dimensions: approximately 15cm x 22.8cm, thickness approximately 3cm
Inner sheets: approximately 12.7cm x 20cm
There are 30 sheets, so it can store 120 business cards.
When I tried putting in a business card I received recently (5.5cm x 9cm), it fit perfectly. I don't think slightly larger cards would fit. I'm listing it because it seems a waste to throw it away.

There are no smokers or pets in the household.