Morrison Clock Gauge No. 818. The Morrison clock gauge displays the liquid level reading of product stored in an above ground tank. Measures the liquid level up to a maximum of 12 feet in height. Measure accurate to 1/8 " can see the gauge easily from 30 feet away. Gauge can be turned in the direction you want after it is installed. Easy to install and calibrate. Threads into a 2 " opening on top of tank. Comes with tube ( not shown in picture ) for cable to hang in with float, tube protects float from turbulence when filling tank. New, these sell for $ 511.00 at JME Ellsworth , on Amazon or ebay new $ 467.00 . If you have a big tank that is hard to get up on top to measure or you are just tired of wondering how much fuel you have on hand without climbing a ladder and using a stick, these work great. I have 3 of them. $ 300 each or I will negotiate price if you take all 3.