Master Precision Level, 15" (380 mm)
Ground and graduated main vial of 10-second accuracy; one division equals 1/2 thousandth (0.0005) of an inch per foot, or 0.04 mm per meter
Main vials have seven graduations on each side of the bubble
Auxiliary level vial shows lateral position and assists in horizontal setting
Level vials are positioned so breakage is reduced to a minimum
Fool-proof adjustment to avoid tampering, once set
Special alloy iron used to obtain freedom from thermal effects
Castings are thoroughly seasoned and machined
Reference surface is scraped
Non-machined surfaces have a black wrinkle finish
Insulation from handling by means of top plate of nonconductive material