Question: what is 2u in mm?
Answer: Many rack-mounted power systems and power supplies are specified as being 1U, 2U, 3U, etc. ... To be precise, 1U equals 1.75-inches (44.45mm) of rack height. Therefore, a 2U rack mount height would be 2 x 1.75”, which equals 3.5-inches high. A 3U height would be 3 x 1.75” = 5.25-inches.