A "oeshort shank" hook is an interesting tool for a tier. If you tie a standard length pattern on a short shank hook, you select one size larger than normal - a size 12 Adams fits on a size 10 "oeshort shank". This does two things that may be beneficial....
In the early days of fly tying and fly-fishing, "oewet flies" were king. Dry flies and nymphs today are more popular, but wet flies, which are fished subsurface, are still very successful for catching trout, steelhead, and salmon. Wet flies do not closely...
The 1650 Tube Fly Hook has the same shape as the 1640. This hook features 2X-heavy wire which makes it great for large trout, steelhead and salmon tube flies. 1650 has 2X-heavy wire.