Lightweight keel can be divided into two categories, namely, ceiling keel and wall keel, which the former one consists 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 consists of cross keel , vertical keel, cross arm keel and various component parts, including Q50(C50), Q75(C75), Q100(C100)and Q150(C150) four series.