Last fall, Google Labs introduced "Mail Goggles," a feature which, once enabled, tasks email composers with solving a few simple math problems before firing that off that email that could potentially fire you back, assuming you were about to send an angry letter to your boss from a drunken stupor. But you don't have to be drunk to regret sending an email, so Google Labs' latest feature lets you unsend a Gmail message you might later regret.

Called "Undo Send," you'll have five seconds to take a mulligan on that Gmail message, which gives you enough time to declare 'Oh s**t!' and still unsend that message you inadvertently set for "reply all," but leaves little time for fumbling the mouse in a panicked state.

"Adding a delay could be potentially frustrating," said Keith Coleman, Google product manager. "We may decide to add longer options."

Coleman indicated there's an option to increase the unsend time window to 10 seconds, though after installing this feature, we saw no option beyond 5 seconds.

You can find the "Undo Send" feature in the Labs tab under Settings.