hwKlaxon

hwKlaxon is a powerful device monitoring tool, which can display notifications, when the following events occurs:

• USB devices connected or disconnected (theoretical speed can be displayed)
• Thunderbolt devices connected or disconnected
• Bluetooth devices connected or disconnected
• Network related events, including WiFi network connections, Ethernet link state changes, and IPv4/IPv6 address changes
• Volume mounted or unmounted (including network volumes)
• Change of the selected default audio device
• Power/Battery related events
• support of the legacy Firewire or ExpressCard events

Wide variety of configuration options are available, notification types can be disabled, devices can be ignored and USB devices can be renamed. The menu bar icon can be configured to hidden to conserve space.