Not quite that light, but I got the deal of the century when I stumbled across a Marmot Essence ultra-light shell at TJMAXX for $59.95. I grabbed it faster than you can say, “what deal for a $190 jacket”..
It’s a gossamer thin shell with Marmot’s waterproof “breathable” Membrain Strata laminate. Fully taped seams. Men’s MEDIUM weighs 6.1 ounces. Zipper chest pocket.
I don’t expect it to be particularly rugged, but the whole point of a rain shell is to mostly sit in the bottom of the pack and get worn as little as possible… I liked it so much, I got the matching pants (5.6 ounces), so I have a complete rain suit in the bottom of my pack what weighs 11.7 ounces)
I do grab this one for around town on a hot summer day with rain as it’s light enough to not boil me. I’ve hiked with it a couple of times. Not bad at all.
No complaints at $59.95.

