This plastic D battery conversion box provides a simple, durable solution for powering gas water heaters, gas boilers, and RV water heaters that use D cell batteries. It converts standard D batteries into the required battery format and supports parallel connections to extend runtime and improve conversion efficiency. Key benefits Multifunctional compatibility: Designed for gas water heater battery boxes, gas boiler battery boxes, and RV water heater applications. Works as a D battery conversion box and D battery adapter for multiple small appliance setups. User friendly design: Easy to install and maintain with a straightforward wiring and mounting approach. Suitable for field service or quick replacement without special tools. Durable construction: Made from robust plastic for long term use and stable performance. Built to withstand repeated installation and removal while maintaining reliable battery contact. Performance and flexibility: Supports parallel battery conversion to increase available runtime. Provides consistent power delivery for devices that require D cell input. Compact and practical: Space saving form factor fits common battery compartments and heater enclosures while leaving room for wiring and access. Compatibility and attributes Function: D battery adapter and conversion box for powering control modules and pilot systems in gas water heaters and boilers, and for RV water heater systems. Material: plastic housing designed for durability and insulation. Connection: Accepts standard D cells and supports parallel configuration to boost capacity and extend operating time. Maintenance: Simple access to contacts for cleaning or replacement to maintain consistent performance. Typical applications Home gas water heater: worn internal battery holders to restore reliable ignition and control for domestic water heaters. Gas boiler service: Use as a replacement battery box during routine maintenance or system upgrades to ensure stable power to the control circuit. RV and mobile systems: Install in recreational vehicles to adapt D batteries for on the road hot water systems or to extend battery life during trips. This conversion box is a practical, no fuss component for technicians and users who need a reliable, adaptable D battery solution for water heaters and boilers.