Microsoft on Tuesday announced a refresh of its Surface Pro tablet-laptop computer. Although Microsoft said the fifth generation of the unit has been redesigned from the inside out with more than 800 new custom parts, the Surface Pro looks similar to its predecessor. “If you were looking for a major redesign of Surface, this isn’t it,” said Ross Rubin, principal analyst at Reticle Research. Nevertheless, Microsoft has made some significant improvements in the tablet cum laptop. Battery life has been boosted to 13.5 hours.