A barrel gasket is typically an isoprene tube (synthetic rubber) with its own lubrication that is placed between two precast concrete barrels. The gasket helps seal the manhole from water intrusion or leakage at the joints. Barrel gaskets are also made from other materials so that they can be used with different water types and water chemistry. Barrel gaskets are used in conjunction with tape coating and a concrete sealant to seal the joints in the manhole or sump.