The Ultradyne C4 Folding Rear Sight, 7.62/.308 offers something you probably associate only with traditional optics, not iron sights; ballistic abilities. You'd be wrong though, with the C4 from Ultradyne having 50-yard ballistic increments designed into the sight from 200 to 600 yards. Is it the most advanced folding sight system ever? Maybe. The Ultradyne C4 Folding Rear Sight take advantage of the natural benefits of the circle-within-a-circle sight picture that naturally works with how your brain already wants to aim. Target acquisition gets faster and accuracy gets better. Don't cover your target, look at it! Single-handed flip up operation Ballisticall Mfg: Ultradyne Usa