Duct Calculation Slide Rule

This is the one that all hvac guys should have. This show how to caculate the cfm for flex

Good Deal, Very Happy.

It's just what the doctor ordered.

Must have if your going to properly size duct work

My package only came with the user manual and not the actual duct slider tool when in the description it clearly says it comes with it. I didn't pay $59 for just a user manual. Like how does a mistake like that happen.Update:So I received the replacement for this shipment and once again it only came with the user manual. Not the actual duct slider tool. I ordered the actual tool and manual from the ACCA website. Much better off doing that for an additional $10 but it comes with everything including other resources. Pic above is what came from ACCA not Amazon. Don't waste your time or money.