What are the safety features to consider when choosing a ski and bike helmet?

When choosing a ski or bike helmet, consider safety features such as impact protection, proper fit, ventilation, and certification standards. Look for helmets with durable outer shells, impact-absorbing foam liners, adjustable straps, and ventilation to keep you comfortable. Make sure the helmet meets safety standards like ASTM or CPSC certification to ensure it provides adequate protection in case of a fall or collision.