Unheard (3.5e Feat)
From D&D Wiki
You are adept at moving without making any noise.
Benefit: You gain a +10 bonus on all Move Silently checks. Blindsense and Blindsight that rely on sound don't detect you automatically, only if the creature succeeds on a Listen check against your Move Silently check. Also, you suffer no penalty on Move Silently checks while moving at your full speed, and only a -5 penalty while running or charging.
Normal: You can only move up to half your full speed with no penalty. You suffer a -5 penalty to Move silently checks while moving at a speed greater than half but less than your full speed, and a -20 penalty while running or charging.