Spirit Levels

1). Heavy duty aluminum alloy frame thickness=1.4 1.8±0.1mm and colour oxidized coated.Double datum planeare milled finish.2).3 pcs of entire level vial indicate level, 45° and plumb with viewfinder,which 90°bubble could be observed from the window. .3)Tolerance of accuracy:0.029°=0.5mm/m based on main datum plane and 0.057°=1mm/m on opposite datum plane.4).Soft cover is slide-proof, shockproof and protects ruler body.5).Wrapped with shrinking film and then packed with knapsack.