Hembra a Hembra 52mm-52mm 52-52 Doble Lente Acoplamiento Inverso Macro Anillo Adaptado

This Double Coupler can connect any 52mm female to 52mm female thread, by using this you can couple filters, hoods, adapters, extension tubes, lenses etc. Can be used for a variety of functions, for example you can reverse a secondary lens to couple to your main lens and use as a macro reverse adapter.

eBay