I've noticed a lot of places dont say. They just say Sitka Ambient. There is also a 200 version. I dont know what's what and it's confusing. I am wondering if there is just an older single model but now they've introduced a lighter or heavier model. It's not the 75 because the bottom half of that one is grid fleece. It's a 100 or a 200.Is this the 100 or 75 version?