· Not Compatible With Other Model Baby Monitors(Including HB65/HB50/HB6550pro)：Only for HelloBaby Baby Monitor Camera HB6550-1. Please check the version to avoid purchasing the wrong model. *Individual monitors can only for U.S. addresses.· Baby Monitor 5 Inch Screen: Could compatible with 4 HB6550 cameras units. (One cameras could not compatible with 2 monitors simultaneously).· Camera Unit Not included in this package: 100v-240v compatible power adapter included. Before purchase, please contact us first!· Not Compatible with HelloBaby Brand Other Model: Only for HB6550-1. Other model like HB6550pro/HB65 are incompatible.· Smart Baby Monitor With Many Functions: VOX Mode: 5 inch big screen baby monitor, sound level LED indicator, 4 Camera expandability, room temperature monitor and alert.