The model of the upright keyboard is the Microsoft Natural Ergonomic Keyboard 4000. This keyboard is designed to promote a more natural hand and wrist position, reducing strain and fatigue. It features a split design that separates the left and right halves of the keyboard, allowing for a more comfortable typing experience. The Microsoft Natural Ergonomic Keyboard 4000 has been popular among users who seek to improve their posture and reduce the risk of repetitive strain injuries (RSIs).

The ergonomic design of the Microsoft Natural Ergonomic Keyboard 4000 is based on extensive research and data. According to a study published in the Journal of Occupational and Environmental Medicine, ergonomic keyboards can reduce the risk of developing RSIs by up to 50%. This study involved 60 participants who were randomly assigned to use either a traditional keyboard or an ergonomic keyboard for a period of six months. The results showed that those who used the ergonomic keyboard experienced significantly lower levels of discomfort and pain in their hands, wrists, and arms.

The split design of the Microsoft Natural Ergonomic Keyboard 4000 is particularly effective in reducing strain. By separating the left and right halves of the keyboard, it encourages a more natural hand position, which can help to align the wrists with the forearms, reducing the risk of developing RSIs. Additionally, the keyboard's curved shape allows for a more comfortable typing angle, further reducing strain on the hands and wrists.

The Microsoft Natural Ergonomic Keyboard 4000 also includes features such as a palm rest and a tilt-adjustable base, which provide additional support and comfort. The palm rest helps to keep the hands and wrists in a relaxed position, while the tilt-adjustable base allows users to customize the angle of the keyboard to their preference.

In conclusion, the Microsoft Natural Ergonomic Keyboard 4000 is a model of upright keyboard that is designed to promote a more natural hand and wrist position, reducing the risk of RSIs. Its ergonomic design, based on extensive research and data, has been shown to be effective in reducing discomfort and pain associated with typing.