safeshine products can prevent your products from lost,you keep the parent unit and keep the sub-unit with your products, if the protected object exceeds to the allotted distance, both the parent unit and the sub-unit will make a sound DID .... with the red lights shining then you should check out the protected object immediately whtther they are forgotten or stolen.if so, you could recover it along the voice of the sub-unit,you should better turn off the parent unit and focus on the voice DID ...from sub-unit if the case happened in the crowed public