A “deep-water” PFD is not suitable for kayaking, even in offshore waters. The highest-grade PFDs have a Level-275 safety rating, and they suit commercial use only in extreme maritime conditions. Level-150 is for open water, and Level-100 is for use in sheltered open waters. Level-50 PFDs are the same rating as the old Type II PFD buoyancy vest. When you’re buying a kayaking PFD, it will have a 150 to 100 rating.