It is a four-cornered guide in the Sanwa standard.
Sanwa (Sanwa) can only be mounted lever.
Q. What is a guide?
A guide is a frame that controls the movement of the lever.
A quadrilateral guide refers to a frame in which the internal space is in the form of a quadrilateral, and has the advantage of accurately entering diagonal input .
However, since it feels like the lever is hitting the guide, it tends to be difficult to adapt easily if you get used to the shading .
Most Korean arcades use Mugak guides.