Stainless steel flat-head wall screws (2/set): length 30.5 mm; screw body diameter 3.85 mm; screw head diameter 8 mm. Compatible and essisential for Nest thermostats. The flat-head screws ensure the perfect mounting of the Nest base to the wall or dry wall, avoiding the disconnection. The regular round or pan-head screws don't work for Nest Thermostats. This screw is fully compatible with all the generations of NEST thermostats including 3rd, 2nd, 1st, E and New released in November, 2020. Be aware: this wall screw is Not the plate screw and it does NOT fit the NEST OEM rectangle metal plate for the electric box!