Increased Blocking Speed is a Special Modifier.
Diablo II pre-v1.08: Could only be found on Culwen's Point, but it had no function.
When Diablo II: Lord of Destruction came out, it could be found on numerous unique and Rune Words for shields, the modifier also gained a purpose by helping against becoming block-locked, and lets your character block more hits, if multiple strikes come in a short period of time.
