YK-2100 Series ...
YK-2123 Blow molded plastic with attachment to riser face.
YK-2123RS Blow molded plastic with arm rests and padded inserts. Attachment to riser face.
YK-2163S Blow molded plastic with arm rest and riser mounted standard.
YK-2165RS Blow molded plastic with arm rests and padded inserts. Floor mounted standards.