The key is located at this time in the animation.
Activate this option if you want to protect a key from inadvertently being edited.
Use this setting to mute a key. When a key is muted, any interpolation or change in value(s) between the muted key and the subsequent key will not take place. Once the animation reaches the next key, values will instantly jump to those contained in that key. Muting a key turns the animation for that key off until the next key is reached.