Complex sentence: Type I and II use a 100-pin stacking connector, while Type III uses a 124-pin edge connector, i.e. connector for Type I and II differ from Type III, which supports a card edge.
Split into simpler sentences: Type I and II use a 100-pin connector, while Type III uses a 124-pin edge connector. The connector for Type I and II differ from Type III, which supports a card edge.