We are able to sit down and discuss the new Microsoft mouse line with Melinda Graetz, Communications Manager for Microsoft Hardware. Here is an excerpt:

ActiveWin.com: How has the battery life been improved in the new Wireless IntelliMouse Explorer and the Wireless Optical mouse?

Melinda Graetz: With the new enhanced Microsoft Optical Technology, most users will experience up to six months of battery life. On average, the battery life of wireless mice with new Microsoft Optical Technology last about three times longer than other wireless mice available. Battery life varies with the amount of wireless mouse usage and previously, average battery life could last from a couple weeks to a couple months. Additionally, the new Microsoft Optical Technology is designed to minimize battery drain with three unique power-saving modes�active, idle and dormant�with imperceptible latency for maximum performance. When the mouse is moving it is in active mode, offering signature Microsoft optical performance. The mouse goes into idle mode if it stops moving, using minimal power. When the mouse has been idle for 10 minutes, it goes into dormant mode � the most power efficient mode. In both idle and dormant modes, the mouse wakes up to active mode immediately when moved so that latency is indiscernible.