... , 3) Unlock module, 4) Frequency: 1.8G, 1.9G Wireless doorbell with DECT,CL-3624 Technical Specifications1. CE (EMC LVD TBR6)2 ... the handset to unlock the door (optional)4,Waterproof with IP 655,Full hands-free speaker6,High quality sound7,High anti-interfere8,DIY installation