GL II type is steel double circuit (two rows) or multi circuit (four rows) air heat exchanger. The finned tube is made of 10 × 0.3 mm steel strip wound by 18 × 2 mm seamless steel pipe. It is in the shape of screw. It can be made up of various surface tubes and long rows of tubes. The inlet and outlet pipes are on the same side. The working medium heat source is steam or high temperature water, and the cold source is low temperature water or salt water. It can be used as air heater or air cooler. It is an economical and durable general radiator. 

The numbering method of GL Ⅱ is as follows:
Model - number of rows - number of surface tubes - length of surface tubes (inches) if four rows are used, the number of surface tubes is 10 and the length of tube is 42 inches, it is GL ii-4-10-42