the Smart Doorbell market are low concentration. The top five producers account for about 41.49 % of the revenue market. Global production of Smart Doorbell were about 2353.68 K Units in 2015, and reach to 2879.99 K Units in 2016. From 2011 to 2016, the annual growth rate was about 19.79%. http://www.qyresearchglobal.com/goods-809054.html