PeakHour is a beautiful, real-time network-traffic visualizer that lives in your menu bar. It provides an instant view of your Internet or Wi-Fi activity in real-time. PeakHour is great for monitoring your Internet or Wi-Fi connection, and can help you determine how much bandwidth your computers and devices are using at any given time.
Note: PeakHour requires a capable, SNMPv1-enabled device to work properly. Many good routers do support SNMP but not all do, so it is important that you check before purchasing.