Free for all rangers, and rangers only!
Granted at L9 (maybe later, but no sooner).
Works similar to stunning fist: DC = 10 + half char level + DEX mod + items + enhancements/feats). The Stunning postfix should be added for bow types as well, but not xbow types.
Works in conjunction with IPS; does not work with Manyshot.
Make it so Turbine!