X1 Extreme 1st Gen ThinkPad
Type 20MF
https://psref.lenovo.com/syspool/Sys/PDF/ThinkPad/ThinkPad_X1_Extreme/ThinkPad_X1_Extreme_Spec.PDF
Build quality - definitely NOT military grade toughness. Screen already prone to white spots (pressure marks) unlike the sturdy Dell XPS 15.