Lightweight keel can be divided into two categories,namely,ceiling keel and wall keel,which the former one c***ists of carrying keel(the main keel),cladding keel(auxiliary keel),as well as various component parts ,covering D38(UC38),D50(UC50)and D60(UC60)three series.D38 is used for 900-1200mm(distance between hoisting points)none people ceiling;D50 is used for 900-1200(distance between hoisting points)human-touch ceiling;D60 is used for 1500mm weight-increase ceiling.U50 and U60 are for cladding keel.Wall keel c***ists of cross keel ,vertical keel,cross arm keel and various component parts,including Q50(C50),Q75(C75),Q100(C100)and Q150(C150) four series.