Solid 1/8” aluminum. Overlaps the edge of the turret hole opening all the way around by 1 1/2". Installation will require drilling holes and purchasing hardware and a weather seal. This is very sturdy and is strong enough for a fat guy to stand on it without bending. If you are purchasing from outside of the United States, please be aware that your country will charge you import duties, as well as VAT (value added tax), for European Union members. Those taxes will be collected at the time of delivery. You, the buyer, are responsible to pay any applicable fees, duties, and/or taxes for your purchased item(s). HUMVEE®, HMMWV®, the HUMVEE Vehicle Configuration, and AM GENERAL® are registered trademarks of AM General LLC. Federal Military Parts and its products and services are neither affilia