The Protech by Hirsch SDI‑77XL‑DIR‑LT is a specialized Ladder & Tower (LT) dual‑technology sensor engineered to detect intruders climbing vertical structures such as communication towers, ladders, industrial stacks, and utility masts. Using PROTECH’s AND‑gated Stereo Doppler microwave and passive infrared technologies, the LT version provides highly focused, narrow‑angle detection with Lens D, optimized for steep downward‑aimed applications. Factory‑configured to use Approach‑Only direction control, the SDI‑77XL‑DIR‑LT is designed to detect upward intruder movement while ignoring downward‑moving rain, snow, and environmental motion—a critical advantage for elevated outdoor deployments. Each LT model ships with its specialized look‑down mounting bracket, and installers may choose optional PH‑6 or PH‑6JB ladder mount brackets to simplify positioning on both caged and non‑caged ladders. Rugged outdoor housing, precise aiming controls, and long‑range stability make the SDI‑77XL‑DIR‑LT the preferred solution for vertical‑structure intrusion protection.