Tá an bunús de the scope, or optical sight, are difficult to verify. It is said that at least in Europe in the 16th century, attempts were made to fix spectacle lenses on the butt. It is written that before the 19th century, firearms already had telescope-type sighting devices that could be used for aiming in low-light conditions. Scopes can be divided into holographic sights, inner red-green dot sights, and léasair radharcanna.