The black and silver Zebra midge is a standard in every fly anglers box. 
These have an added strand of flash wrapped with the weird. Putting something a little different in your fly box. 
Tied on a Gamakatsu size RS- 14 hook
(appears to be more like a size 16)
MFC tungsten beads 2.4mm 
Perfect for nymphing Brown Trout, Brooke Trout, Rainbow Trout and even Steelhead. 
Run it as a single nymph, run it on the tag end off your heavier anchor fly, or even use this as the anchor fly. 
However you rig it, know it is well crafted and offering the fish something slightly different then they have seen.