App uses GPS to track stolen devices.

US-based software firm PocketMac has announced a tool designed to help BlackBerry users recover their smartphone if it is stolen.

Available now, BlackBerry ER uses the built-in GPS hardware of most BlackBerry models to report its location to the owner, as well as the phone number of the person using it if they have swapped out the SIM card for a different one.

According to PocketMac, thieves typically replace the SIM card with their own, and if this happens, BlackBerry ER sends a text message to a designated back-up mobile number specified by the user.

The text message includes the number associated with the SIM in the BlackBerry, the unique subscriber identity number of the SIM, and the current geographic location of the device, information which can then be passed to police to help them recover the BlackBerry.

BlackBerry ER costs US$14.97 (AU$18.07) and supports any SIM-based BlackBerry handsets running version 4.6.0 or higher of the BlackBerry platform, according to the firm.