Photo Plus 52mm Diameter Extension Tube / 21mm Long for Nikon ES-1
This is a 52mm diameter straight tube. Both ends of the tube are 52mm (Male and Female). Length of the tube is 21mm (excluding the deepness of the male threads). It is actually a combination of two short tubes. It acts as an extra extension for Nikon ES-1 copying attachment to cope with the problem of digital SLRs with 1.5x crop factor. Made of metal.