The Protech by Hirsch SDI-77XL-HS-H PIRAMID is a high-security, dual-technology outdoor motion sensor with built-in anti-masking protection, engineered for demanding perimeter applications requiring wide-area volumetric coverage. Featuring Lens H, this sensor delivers a broad 90 ft. x 50 ft. (27 m x 15 m) detection pattern — ideal for open perimeters, fence lines, parking areas, and critical infrastructure where expansive coverage is essential. The HS (High Security) designation adds anti-masking components that detect any attempt to block the passive infrared or microwave sensors, locking the unit into a constant alarm until the obstruction is removed. Combining PROTECH's proprietary Stereo Doppler microwave technology with a dual-element passive infrared sensor in an "And Gated" configuration, the SDI-77XL-HS-H reliably identifies slow-moving, fast-moving, and crawling intruders while maintaining an exceptionally low nuisance alarm rate. Ten-position digital range and sensitivity controls allow precise field tuning, while balanced temperature compensation automatically adjusts both technologies to maintain performance from -40°F to 158°F (-40°C to 70°C). Housed in a rugged metal enclosure with a protective weather shroud, the sensor features a user-selectable solid-state Form C relay output, tamper switch, and swivel mounting with 180° horizontal and 90° vertical adjustment. Operating on 10.5 to 28 VDC, the SDI-77XL-HS-H is the trusted choice for high-security perimeters demanding false-alarm-free, anti-masking-protected, wide-area intrusion detection.