Hi guys,
you did not understand me. stevekale, the body is lead coated epoxy + sand. Look here:
Siman Fly-Fishing Shop, Czech Nymph Products, Czech Nymph Masterclass. Weighted Caddis Case
I not catch fish on the this fly. I used the fly only as a weighted fly when the tungsten is small weight ! With the lead fly I must get very small flies (14-18) into a deep and very quickly the river (especially summer). See you:

river Váh near city Ružomberok
depth cca 2,5m
You think that you get to the bottom of tungsten fly? On the competitions you can use to 4.0 mm. No more! Its FIPS Mouche regulations.
Cheers
Peter