Signaling Devices
Tree Stump Listening Device
Visit SPY's Digital Learning HQ to learn about the Tree Stump Listening Device: https://www.spymuseum.org/exhibition-experiences/about-the-collection/collection-highlights/tree-stump-listening-device/
Visit SPY's Digital Learning HQ to learn about the Tree Stump Listening Device: https://www.spymuseum.org/exhibition-experiences/about-the-collection/collection-highlights/tree-stump-listening-device/