Used a short piece of angle aluminum, and drilled four holes in it (two for connecting to the rack, two for the thermos). Drilled and caulked the holes in thermos and bolted it all together with SS nuts and bolts. With the loop on the lid, I can run piece of aircraft cable to lock together the saddle and lid with a U-lock. The lid can't be rotated off (I had the contents of a seat bag emptied once). The heavy black wire is the pic is 1/4 inch irrigation tubing that I use as conduit for the rear light wire.