Concealed panic bars, somtimes called concealed panics or exit devices, are safety bars that span horziontally from the left stile to the right stile of a set of double storefront doors, "rim panic bars is preferred for a single storefront door".
Allows storefront doors to be opened from the inside while locked from the outside.
A lot of cities require you to have a concealed panic bars installed onto your new storefront doors for ADA purposes.
Example usage of concealed panic bars would be if your store closes at 5:00pm and you still have customers to tend to. This way you could lock your storefront door so that customers could leave but customers from the outside could not walk in.
Concealed panic bars have the option of a keyed cylinder on the exterior portion of the storefront door. If your storefront door is for the entrance of your storefront and not an emergency exit then you'll want to add a keyed cylinder lock. If this storefront door is an emergency exit door it may not be necessary to have a keyed lock on the exterior portion of the door, nor a handel.
Concealed panic bars have a rod that runs vertically inside the stile of the storefront door and latches into the frame header and threshold of the storefront door when to storefront door is in the closed position. The rods that span vertically inside the storefront door stile is where the name "concealed panic bar" originates from.