The VT02 Sunamp Optimino Heat Pump & PV Key ensures seamless compatibility between your Thermino xPlus, Vaillant Arotherm+ R290 series heat pump, and solar PV system. This compact key, measuring just 25mm x 25mm x 15mm, simplifies connections and enhances integration, future-proofing your energy needs. Features & Benefits: Seamless Compatibility: Works with Thermino xPlus and Vaillant Arotherm+ R290 series heat pump and solar PV. Compact Size: Measures 25mm x 25mm x 15mm. Simplified Connections: Ensures efficient integration. Future-Proofing: Prepares your energy system for future needs.