Here is my kit:
The rod is St Croix Triumph TRS60LF4 Travel Spinning Rod. It is 6 feet in length, and I opted for the fast action graphite version. It comes apart into 4 pieces for easy transport. When disassembled, it is 18 inches in length. The full rod weighs 3.2 oz as measured (even though it is listed as 3.5 oz). The rod is designed for up to 8 lb test line.
The rod case is one that I made myself fluorescent light tube. It weighs 1.5 oz.
The reel is an Okuma Ultralight UL-10 spinning reel. It was the lightest reel I was able to find, and when I purchased it online I was worried that it would be a toy, but I was pleasantly surprised. It really feels like an actual reel. It has three ball bearings, and can handle line from 2 to 6 lb. I spooled some 4 lb line on it, of which the reel can hold 115 yards. The reel weighs 5.4 oz, and 5.8 oz with the line spooled on.
The tackle is limited, not in number of pieces, but in that it is focused on small freshwater fish. It is comprised of several hooks, split shot, swivels, snaps, and a decent assortment of lures. I also have several floats and flies for some different techniques with which I am not good at all. The total weight of the tackle is 2.8 oz.
That’s the entirety of my "ultralight" spin fishing kit. The tackle and reel are stored in a small bag and are kept in my pack. The rod in the case is strapped to the side of my pack.
The total weight of my ultralight spin fishing kit is 13.6 oz with the bag which holds the tackle and reel.