The timers are readily available for electric openers and are typically used
on apartment house door openers. They consist of a timer box with two
lights, one green which when lit indicates it's safe to drive through the
door opening and one red light when lit indicates not to drive through
because the door is about to close. The timer can be set to start the
close cycle after a predetermined amout of time ususually about two - five
minutes.

Rich
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