be (1000 m / 10 m) / 100 mm = 1 mm projected behind the reticle plane. When 10× magnified the error would be 10 × 1 mm = 10 mm at the ocular. Accessories Typical accessories for telescopic sights are: Lens hood is a tubular extension mounted on the objective and/or ocular ends to shade light and reduce/eliminate glare. The lens hood mounted on the eyepiece, often called an eyecup, is often made from corrugated silicone rubber for resting against the user's eye socket, and can also help avoid recoil-induced collisional injuries and maintain a consistent eye box. Some objective-mounted lens hoods that extend the full length over the gun barrel can improve image quality by shielding out heat-induced mirage ("heat waves", or aberrations resulting from a hot gun barrel). Lens covers or lens caps protect the objective and/or ocular lens surface against foul weather and accidental damage. There are slide-over, bikini and flip-open type covers, without or with transparent covering material. Optical filters such as Grey, Yellow and Polarising filters to optimize image quality in various lighting conditions. Anti-reflection device (ARD) or KillFlash is a usually honeycomb-mesh cover used to filter out light reflections from the objective lens, which could compromise the shooter's position. Laser filters protect the operator against being dazzled/blinded by potential laser light sources. These filters are often an internal part in the assembly of lens elements. Scope cover, a semi-soft pouch that protects the sight from accidental collisions or the elements during transit and storage. Optronic technologies Integrated laser rangefinder In 1997 Swarovski Optik introduced the LRS series telescopic sight, the first sight on the civilian market with an integrated laser rangefinder. The LRS 2-12x50 sight can measure ranges up to . The LRS sights are currently (2008) not produced anymore, but sights with similar features are commercially available from several manufacturers. Ballistic support devices An integrated ballistic computer/telescopic sight system known as BORS has been developed by the Barrett Firearms Company and became commercially available around 2007. The BORS module is in essence an electronic Bullet Drop Compensation (BDC) sensor/calculator package intended for long-range sniping out to for some telescopic sight models made by Leupold and Nightforce. To establish the appropriate elevation setting the shooter needs to enter the ammunition type into the BORS (using touch pads on the BORS console) determine the range (either mechanically or through a laser rangefinder) and crank