The jaws of the vise must be positioned or be able to be positioned at an angle that allows you to tie flies of various sizes with it. Some vises have jaws that are too big to use with a variety of hooks. Others don t have the jaws positioned at an angle that allows the tyer to work with small hooks. Look for a vise that has jaws positioned at an angle that allows you to work around and with the smallest hooks you might someday use. That might be size 28, so check to see if the vise will hold this size hook securely while allowing complete access to the main length of the hook shank.
Many vises have heads that pivot or rotate.
These are nice features you should consider when shopping for a fly vise. Although a rotary feature isn t a necessity, it is a convenient feature you should consider. Many expert tyers use vises with heads that are fixed and don t pivot or rotate. You ll have to decide if these are important features you re willing to invest in. Keep in mind, a lot of extra features won t make a vise hold a hook any better.