Appleton™ Kwiko™ A sealing cement and filler is designed for use with Appleton sealing fittings and sealing hubs. Sealing cement is used, in classified areas, to contain and restrict the passage of gases and explosions from one portion of a conduit system to another. Fiber filler makes dams around and between all conductors to prevent sealing compound from leaking while being poured in its liquid state.