The Honeywell 3500 series military thermostat, part number 3500-00660002, is a hermetically sealed device engineered for critical applications where reliability and durability are paramount. Its robust construction, including a steel housing with a glass-to-metal seal, ensures protection against harsh environmental conditions. The thermostat's open-on-rise action and automatic reset provide consistent temperature regulation, making it ideal for aerospace, military, and industrial equipment. It meets stringent military specifications and offers excellent dielectric strength, insulation resistance, and contact resistance. The Honeywell 3500 thermostat is a dependable solution for maintaining precise temperature control in challenging environments.