A motorcycle has a frame, a structure mounted on the frame, and a locking assembly locks the structure on the frame and has a latch pin mounted on the frame, and a latch housing mounted on the structure and having a passage into which the latch pin extends. A polarizing plate of the present invention is used in an organic EL panel, and includes a polarizer, a first retardation layer, and a second retardation layer. The gun muffler includes a transition section fitted around the gun tube and engaging the gun tube for preventing the escape of residual combustion gases caused by the firing of a projectile by the gun.