The phoropter is used in measuring refractive errors in the eye and is a valuable tool in determining the correct lens needed. This device is made by the Denseng Standard company C.1930. Was acquired from an optometrist personal collection that he got when he was a student in Pacific University. He had it in his personal collection for about 40 years and this device is a rare example featuring the original bracket which is rarely seen (we had one back in 2008). Can be easily wall mounted and the knob makes the device go up and down to position it to the correct height .