2017 Keystone Sprinter 353FWDEN, The 2017 Keystone Sprinter 353FWDEN is a 39-foot-4-inch, 4-slideout rear den fifth wheel with a 10,730 lb dry weight, designed to sleep up to 7 people. Key features include a 55" TV, 18 cu. ft. residential fridge, 4-point auto-leveling, and a 35,000 BTU furnace.