The device comes with 5 thermo/hygro sensors included. It also supports expansion with up to 8 wireless thermo/hygro sensors for monitoring multiple rooms.
dnt is part of ELV Elektronik, which produces 100% of its products in the group's own factory in Zhuhai, South China. (https://de.wikipedia.org/wiki/ELV_Elektronik)
Hello
The display has the dimensions 95x55mm - Diagonal 11cm (or 4.3") according to DNT:
https://www.dnt.de/media/f7/d3/bd/1615390432/DNT000004_roomlogg_pro_datenblatt_v3.pdf
LG