Felton Properties Inc., Portland Ore. purchased the Tower Colorado office building for $9.6 million located at 1720 S. Bellaire St. near I-25 and S. Colorado Blvd. The 127,715 square foot 15-story office building is 99% leased. Felton has plans to invest $1 million in capital improvements including new boilers and chillers, elevator upgrades and improve the building’s energy efficiency.