Standard Features - 6-Square Inch Blue Display - Stages: Heat Pump, Heat / 2 Cool; Multi-Stage 2 Heat / 2 Cool - Non-Programmable or 7-Day Programmable - Large Easy-to-Read Display Characters - For 24 VAC or Millivolt Systems - 3-Wire Zone Valve - Tri-Powered - Hardwired, Battery Powered or Power Stealing Battery Assist