What are the key features to consider when choosing a bicycle helmet liner for optimal safety and comfort?

When choosing a bicycle helmet liner for safety and comfort, consider features such as impact absorption, ventilation, moisture-wicking properties, and adjustable fit. Look for liners with materials like EPS foam for impact protection, adequate ventilation to keep you cool, moisture-wicking fabric to keep sweat at bay, and an adjustable fit system for a secure and comfortable fit.