Bohning Wax Seal-Tite
Works very well and lasts on the string for a long time. Very easy to apply and rub into the string and wipes off the fingers without much effort. The staff at Canada Archery set my bow up and used this on my string, I can safely say it lasted for over 1000 shots before the string felt dry-ish (probably closer to 1400). I forgot to buy a tube with the bow and did some heavy practice over the last month at my home range. String is still in excellent condition, this wax protects quite well
Does what it is supposed to.
Overall works great on your synthetic bowstring, no complaints. Also found that on some arrows if the nock is loose or the ****-in points unscrew easily, applying a small amount of wax will keep the nocks in and stop the point from unscrewing, both without permanently setting in the nock or point, or damaging the inserts. Use hot-melt glue if you require more permanent sets.
This particular brand was highly recommended to me by someone who tried a lot of brands. Works great. As someone else wrote, a little goes a long way.