EN 1621-1 Level 2 is the highest safety certification for ski knee pads, meaning it's been tested to transmit no more than 20 kN of force from a 50 kN impact. That's significantly more protective than Level 1, which allows up to 35 kN of force through to your knee.
Level 2 pads are really designed for FIS racing and high-speed, high-impact scenarios where you're pushing your limits. If you're racing competitively or skiing extreme terrain at speed, that extra protection can make a real difference in preventing serious injury.
The trade-off is that Level 2 pads tend to be bulkier and less flexible than Level 1 options. For most all-mountain and freeride skiers, Level 1 provides solid verified protection without sacrificing as much mobility. Save Level 2 for when you truly need maximum protection or when race rules require it.