Apparently this is the top portion of U-853's periscope.
While i have reservations about it being taken from a grave site, it is educational to see it up close.
The attached backstory:
"
A super rare German WWII Kreigsmarine U-853 Submarine Attack Periscope, recovered in 1962. This is the smaller of the periscopes used on U-Boats, designed for the final stealthy run on a target. This display piece shows the outer tube and lens (showing damage from the depth charge attack that sank the sub), the inner liner with mirrors and individual lenses. It stands about a foot tall and is on a wood base, with the US Navy Diesel Boat Cruise Badge of the gentleman who recovered the periscope. German submarine U-853 was a German Type IXC/40 U-boat of the Kriegsmarine during World War II. She was commissioned on 25 June 1943 with Kapitänleutnant Helmut Sommer in command. U-853 saw action during the Battle of the Atlantic in World War II. She conducted three patrols, sinking two ships totalling 5,783 tons. On her final patrol, U-853 was sent to harass United States coastal shipping. She destroyed USS Eagle 56 (PE-56) near Portland, Maine. Just days before Germany's surrender, U-853 torpedoed and sank the collier Black Point during the Battle of Point Judith. American warships quickly found U-853 and sank her 7 miles east of Block Island, Rhode Island, resulting in the loss of her entire crew. U-853 is a popular deep sea diving site. She rests in 121 feet of water. The lot includes lots of paperwork and correspondence confirming the identity of the periscope."