2X Teleconverter for Bower, Rokinon, Vivitar, Samyang 500mm, 800mm, 420-800mm, 650-1300mm T-Mount Lens The 2x Professional Multiplier is a high-quality teleconverter that delivers enhanced telephoto versatility. It multiplies the focal length by 2x, providing an affordable and portable way to extend your cameras reach. The specialized lens elements virtually eliminate color aberrations. The anti-reflection coating enhances light transmission efficiency, improves color consistency, and reduces flare. Works ONLY with compatible T-mount Lenses -- Uses a convenient T-Mount adapter, and is used between your SLR camera and lens