OLO1957 Features: * Versatile and dependable design, with grooved HDPE out shell, rain trough and accessory slots * Pin lock adjustment is a sturdy, easy to use 4 point pin lock headband * Ratchet adjustment headband offers a firmer and more comfortable fit * All suspension choices feature 3-level height adjustment * Material: HDPE * Testing and approvals: * Class E * ANSI Type 1