This rare Lufft Abbeon relative humidity indicator model AB1 from West Germany is a rare find for collectors of scientific instruments. The brand Lufft is known for producing high-quality instruments, and this one is no exception. Its accuracy and precision make it a valuable addition to any collection. The indicator measures the relative humidity in the air, making it useful for a variety of scientific purposes. This particular model has a measurement range of 0-100% and is in excellent working condition. Its compact size of 5 3/4 inches also makes it easy to display or store.