Microsoft is reinventing the mouse wheel, adding Tilt Wheel Technology for horizontal scrolling and smoothing the vertical-scroll motion, the company said yesterday.

The tilt wheel allows users to scroll left and right as well as up and down without having to use the on-screen navigation bars. This can be handy when working on a large spreadsheet or trying to view an unwieldy Web site, Microsoft said.

Microsoft is planning to launch three mice with the new tilting wheel on September 3, one corded and two cordless operating at 27MHz, a company spokeswoman said. The mice will also have a feature that lets users toggle between open applications on a computer by pressing down on the wheel, she said.

Eight out of every ten mice sold in the US has a scroll wheel, according to Microsoft, which cited research by NPD Techworld. However, users want more, Microsoft said. The vendor said it found strong demand for horizontal scrolling in its own research.

Microsoft rival Logitech is happy that Microsoft is following suit with a button to switch between applications, a feature Logitech introduced a year ago, but isn't too convinced about demand for horizontal scrolling: "It is not to say that horizontal scrolling is good or bad, but the things that customers say they want to do with their mouse are the things we have already implemented," said Lloyd Klarke, a senior product manager with Logitech.

Klarke also said there is a clear purpose for the "clicks" a user feels when scrolling vertically. With Microsoft's new wheel there are no clicks when scrolling up and down. Logitech studied the clicks and found them key to the scrolling experience, Klarke said.

"Customers need some sort of détente, a click, to know that they are moving to the next line. What they don't want is either absent or overemphasized clicks. We spent a long time measuring to get the right feel," he said.

The new Microsoft mice will be sold worldwide. Further product and pricing details will be announced at launch. Pricing is expected to be in line with Microsoft's current mouse portfolio.