SWAROVSKI OPTIK FRR Forehead Rest for EL Range Binoculars with Tracking AssistantThe Swarovski Optik FRR Forehead Rest provides a stable three point support to ensure maximum stability and comfort when observing for extended periods. It is designed for use with the Swarovski Optiks EL Range Binoculars with Tracking Assistant. The forehead rest can be adjusted so that your gaze is lined up perfectly. It is mounted on the focusing wheel in place of the battery cover, whose function it replaces.