Air Conditioner Filter

I found this while doing a major cleaning and am selling it as I won't be using it.

I don't know when it was purchased, and it has been stored for a long time.
It has only been opened for inspection.

Since I have never used it myself, I do not know how to use it or which models it is compatible with.
Please examine the product photos carefully and only consider purchasing if you know how to use it!

[About Shipping]
I will remove the contents and fold the box to fit the size for shipping via Yu-Packet Post.

Seller: Musashino Shizai Co., Ltd.
Product Name: Premium Air Conditioner Filter
Quantity: 1 piece
Size: Approx. 38 x 80 cm