Plain bearings consist with integral shank forming a housing and a spherical plain bearing,or a spherical plain bearing inner ring ,or a spherical plain bearing inner ring and a sliding layer between the bore of the head and the inner ring. As a rule, Plain bearings are available with left or right-hand female or male threads. HIANA Plain bearings have the sliding contact surface combinations steel-on-steel,steel-on-bronze,steel-on-PTFE composite material and steel-on-PTFE fabric.