Do not use fast flight strings on older bows.

Have to use a string made of dacron B50 string material. Older bows, like yours, do not have reinforced limb tips needed to handle the extra shock from a low stretch fast flight string.
The difference in speed using fast flight and dacron strings is negligible. I have experimented with both and about 5-7 FPS differnce. I think bow shooots much quieter too with B 50 string

What model Bear is it?