All types of Diamond Chain meet ISO 9001 certification which sets the standard for quality in the chain industry. All package of chains include  530 XDL (extra strength self lube)- Diamond's performance proven chain combines thicker link plates, a high capacity modified press fit coverside with constant lubrication in the pin bushing area to deliver higher strength while requiring fewer adjustments and less maintenance.. Connecting Link. XDL. By: DIAMOND CHAIN CO