The Höppler principle is used to measure the viscosity of Newtonian liquid by measuring the time required for a ball to fall under gravity through a sample-filled tube that is inclined at an angle. The average time of three tests is taken; the result is converted into a viscosity value using a simple formula.Two models are available:KF30 has a fixed angle of 80° and complies with DIN 53015KF40 can be angled at 50°, 60°, 70° and 80°.