The flashing, or blinking, is most likely caused by a low battery condition. Please replace your battery with a brand new 9V alkaline battery with an extended expiration date at least 3 years out from the current date.
Zircon stud finders require a robust, fully charged 9V alkaline battery to properly operate. This is especially important with models with backlit LCD screens.
The Wood Stud SuperScan® requires two AA batteries and the MultiScanner™ x85 requires three AAA (LR03) batteries.