Pro Drop Weight is a newer and unique shape in the world of fly tying creativity. Pro Drop Weight are made of Brass and are on the heavier end of the Brass spectrum. Cone Disc can be installed traditionally on your tube fly but are also designed to have the larger or "flared" end of the weight facing forward on the fly creating erratic pulsating fly action when stripped. The heavy flared end will prop wings tied directly against the disc "propping" winging material into the current for additional movement. Pro Cone Disc can also be utilized in creating shoulders for flies that are tied in the round utilizing standard or composite dubbing loops. Pro Drop Weight Specs Small (10 pcs/pk): 0.40 grams/6.17 grains Medium (10 pcs/pk): 0.60 grams/9.26 grains Large (9 pcs/pk): 0.80 grams/12.35 grains X-Large (8 pcs/pk): 1.00 grams/15.43 grains ** Pro Sportfisher Pro Drop Weight will fit all: Pro Microtube, Pro Nanotube, Pro Flexitube 40/40 and Pro Classic Medium tubing options**