The Alcovisor Jupiter and Mercury devices have a :15 count-down feature that can be enabled. You can access this setting in the Advanced Settings menu. By enabling the :15 count-down feature, the Jupiter and Mercury devices will automatically go into a :15 wait period immediately following a Screening Test result of .020 or greater. When the clock expires, the device will prompt the operator to begin the Confirmation Test.
The Mark V device does not have a :15 count-down feature. In this case, the operator would need to set a timer to fully observe the :15 wait period before administering a second test, which is the confirmation test.