The shield consisted of several layers of wood covered in a layer of bronze with a layer of leather in between, to absorb shock. The shield had an strap in the middle of the shield and an handle at the right edge. The shield usually had some emblem painted onto it.
In Greek warfare, the hoplon was the most important piece of equipment of the hoplite (heavy infantry). Its large size covered a large portion of the holder's body and its weight (24 lbs) allowed it to deliver crushing blows. Vital to maintaining the effectiveness of the Greek phalanx, the left third of the shield would protect the right flank of the man to the holder's right, hence why losing it was considered to be a disgrace.
After the battle, the hoplon was often used as a stretcher to carry the dead and wounded from the battlefield. In the event of a retreat, the shield would usually be the first thing discarded. These two facts gave birth to the phrase "Come back with your shield or on it." which Spartan women told their husbands when they left for battle.