Abstract: A device that attaches to a bag provides an indication when the volume of matter in the bag reaches a predetermined value. The device includes a detachment detector that provides a detachment signal when the device detaches from the bag. First and second arms may be pivotally connected to each other and biased in a direction towards each other adjacent first ends of the arms. The first and second arms in use engage opposing sides of the bag. At least one bag level indicator provides a bag level signal when the volume of matter in the bag reaches the predetermined value.