This is a replacement cylinder for Miwa Lock. It is often used for entrance doors of apartments, houses, and offices. Since it is a two-key system, you can lock and unlock the upper and lower locks with one key. Four keys are included. It was used on the entrance door of an apartment building, but it was not exposed to rain. Brand: MIWA LOCK Accessories: 4 keys All keys are genuine products. Condition: Used Color: Gold It is not necessary to have a two-door-two-lock system to use this. The keys and the lock body are believed to be of the same specifications, so you can install it on another door without being limited to a two-lock system. Of course, you can use only one and keep the rest as spare parts. I have added a little more information. *Due to the nature of keys, we will only conduct transactions with anonymous shipping, and we cannot accept returns or refunds. Please consider carefully before purchasing. The product will be shipped in the box of the replaced product as "PC parts" via Yu-Packet Plus. *Because it is a used item, there are some signs of use, dirt, and scratches. Please refrain from purchasing if you are sensitive to these issues, and only purchase if you understand. We will also accommodate bulk purchases. Thank you for viewing.