The Robens Geographic is a lightweight folding stool that deploys and folds literally in seconds. At 350 grams / 12.4 oz, it offers light weight and high strength without the price tag of ultralight carbon fiber accessories.
It's fairly easy to set up three legs on uneven ground but they are inherently less stable than four, and the small footprint of a compact stool doesn't help. Take care when placing the stool on the ground and sitting on it. Thankfully, the Geographic High deploys so quickly that you can take breaks more often. This helps you maintain a high enough cognitive functionality to operate it correctly.
Does not need assembling: just whip it out and spread the legs. Comes with a lightweight carrying bag.