These Timber Stop Logs feature a “tongue and groove” design with a gasket to reduce leakage. The gasket is protected inside the “groove” and will stay in position as the logs are stacked. The gasket is easily replaced if it gets damaged. These particular stop logs will be stacked by hand and do not feature a lifting device. They are effectively 100 pounds per piece and easily handled by 2 people. The Tongue and Groove design makes for an extremely strong horizontal strength as the logs work “together” to hold back the water.