Complex sentence: This type of armour is a poor conductor of the shock wave, and furthermore "spall liners", made of materials such as Kevlar, are commonly fitted to the interior surface of the armour, where it acts to retain any spall that does occur.
Split into simpler sentences: This type of armour is a poor conductor of the shock wave. "Spall liners", made of materials such as Kevlar, are commonly fitted to the interior surface of the armour where it acts to retain any spall that does occur.