Cooling With Optional Electric Heat And Gas/Electric Models 12½-17½ Tons Standard Efficiency - 12½ Tons High Efficiency - Roof Curb; Cooling With Optional Electric Heat And Gas/Electric Models 12½-17½ Tons Standard Efficiency; 12½ High Efficiency - Downflow Duct Connections - Field Fabricated; Cooling With Optional Electric Heat And Gas/Electric Models - 12½-17½ Tons Standard Efficiency; 12½ Tons High Efficiency - Horizontal Unit Supply/Return And Unit Clearance - Trane Voyager TC* User Manual