Rotation Molded Polyethylene Dock Floatation with Expanded Poly Styrene Foam Filling. Buoyancy 434 lbs in fresh water A vent plug is included and needs to be installed before use. For orders of 6 or more, you may want to call for a bulk shipping rate. Pallet shipping needs to go to a commercial location with a fork lift or loading dock unless you pay extra for a delivery truck with a lift gate. Shipping locations need to be trailer truck accessible. (no camp roads) Otherwise, UPS ground is the best shipping method for these items.