I have the PACT original model. You can set it to multiple screen spacings howver I use 2 feet as that is the length of the mounting bar. Calculates SD, ES and mean absolute deviation. You may shoot a screen but not the unit as it's on the bench .Has an infrared printer capability which i don't use. Had mine since the mid-80's and had no beef with it. I recently sent it back to PACT as it suddenly started missing rounds. I suspect 25 year old screen issues but am waiting for their prognosis. It is supposed to be under warranty.