... bronze power dry bearings (with PTFE/Pb, with PTFE without lead, with PTFE/fibre without lead, with PTFE/fibre),aluminum alloy ... ), steel bronze powder marginal bearings(withPOM, with PVDF, with PEEK/PTFE), metal with PTFE layer dry bearings, metal meshwith PTFE ... layer bearings, bronze powder with PTFE tape bearings, steel with PTFEfibre fabric bearings3) Metallic self-lubrication ...