The Personnel Marker Light (PML) is a safe chemical light approved by the USCG and the FAA for use on life preservers. Squeeze handle to activate. When activated, the PML emits a yellow-green glow which lasts for a minimum 8 hours and is visible for up to one (1) mile on clear, dark nights. A superb emergency light source for life preservers as it is waterproof, windproof, nonflammable, easy to activate, and requires no batteries. Four year shelf life. Includes stainless steel clip for attachment to life jackets and vests.