Can anyone tell me the specifications of the auxiliary keels for household ceilings?

The wooden keels used for suspended ceilings are generally 3*4CM. Light steel keels are rarely used for home decoration. The specifications are generally two series models: 50 type and 38 type! There are two types of galvanizing for keels, one is hot-dip galvanizing and the other is cold-dip galvanizing. The price of hot-dip galvanizing is high, while the price of cold-dip galvanizing is low. The ceiling keel is composed of a load-bearing keel (main keel), a covering keel (auxiliary keel) and various accessories. Divided into three series: D38 (UC38), D50 (UC50) and D60 (UC60). D38 is used for the suspended ceiling with a hanging point spacing of 900-1200 mm and is not accessible to people. D50 is used for the suspended ceiling with a hanging point spacing of 900-1200 mm. D60 is used for the suspended ceiling with a hanging point spacing of 1500 mm. U50 and U60 are covered keels. Used in conjunction with load-bearing keels.