In recent years, air conditioning jobs have become increasingly increasing. Designed calculations for these executions, but you cant have to repeatedly run through a very messy calculation, this duck meter will make it very easy to seek the numbers you need. In addition, the reverse side has a tape measure for cold water piping, which gives the user more convenience. This is a calculation scale that is widely used by air conditioning technicians, as well as hygiene equipment manufacturers, company design rooms and businessmen.