SHELTON, CONN. — CBRE Group has arranged the $16.73 million sale of 6 Armstrong Rd. in Shelton on behalf of an entity controlled by Marcus Partners Inc. New York-based Windsor Management Corp. purchased the property, a 163,287-square-foot office building located between exits 11 and 12 off Route 8. The property was 87 percent leased at the time of sale. Occupancy increased from the 50 percent mark 12 months earlier, thanks to a $2.2 million capital investment program that included HVAC, restrooms, lobby and common area upgrades as well as expanded parking. Jeffrey Dunne and Steven Bardsley of CBRE’s Institutional Properties team negotiated the transaction; CBRE also procured the buyer.