The W4 Single Backing Box (Berker 21261) is a high-quality electrical backing box with an external double cable clamp for secure installations. Measuring 49mm in diameter with a 45.5mm insertion depth, it features two rear line entries and one knockout opening for flexible wiring options. Flame-resistant to VDE 0606-1 standards, it’s perfect for safe and reliable use in caravans, motorhomes, and other setups
