ENHANCED BRIGHTNESS - Upgrades your forend WeaponLight with a high-output 500-lumen LED, significantly improving visibility in low-light conditions for superior target identification. EXTENDED COMPATIBILITY - Designed to fit multiple forend WeaponLights including 617, 618, 620, 621, 623, 328, 628, 629, 636, 917, 918, 920, 923, and 936 models for versatile use. ROBUST DURABILITY - Features a Mil-Spec hard anodized aluminum construction, ensuring resilience against impacts and harsh environmental conditions for reliable long-term performance. OPTIMIZED BATTERY LIFE - Provides a 1-hour runtime on high, balancing powerful illumination with efficient energy use, powered by a single CR123A lithium battery (not included).