The Trijicon ACOG (Advanced Combat Optical Gunsight) is a fixed power” compact riflescope with an illuminated reticle pattern for use in bright to low/no light. The ACOG is designed to be extremely durable and reliable. Combining traditional” precise distance marksmanship with CQB speed” many variants include a bullet drop compensated (BDC) reticle. Every feature of its design was chosen for a single purpose: to provide increased hit potential in all lighting conditions. With the Trijicon ACOG 3.5×35 LED riflescope” users can select from six adjustable brightness levels with an “off” between each setting” allowing the user to determine how much to illuminate the reticle – even in transitional lighting. Powered by a single AA battery” the LED ACOG can run for over 12″000 continuous hours (on setting #4). Like all ACOG models” the 3.5×35 LED is designed with a forged 7075-T6 aircraft-grade aluminum alloy housing” making it nearly indestructible. Includes a TA51 Flat Top mount.