Heated display cases range from full-service to self-service and revolving merchandisers. Most warming and display equipment requires 120V electrical power while other larger units may require 208V/240V connections. Some heating systems eliminate the condensation and water involved with conventional equipment resulting in less food waste. Newer hot dog roller grills can record the temperature of the grills and automatically adjust the temperature to ensure safe food holding. Two-in-one units feature steamers that keep the food hot after first cooking it. Water softeners may be necessary for units that require water and they should be cleaned regularly to prevent buildup.