Green beret gives your soldier 10% chance NOT to make noise, when otherwise he’d make some. It’s also the lighest item, with 0 bulk. Excellent if you want to sneak around.
Starlight scope removes the sight range penalty at night, when stationary. That means, if you stand still, your Ranger get’s all 650px sight range, even at night. Keep in mind that assets still are 3x times harder to spot, so stay wary of the mines. With it, you can easily ambush VCs at night and keep them out of their spotting range, giving you massive adavantage if you play it out right.