NightForce Clamp-on Power Throw Lever NightForce customers love the fast magnification changes in all conditions provided by the threaded Power Throw Lever PTL that is included with many of our scopes. It allows instant magnification changes, even while wearing gloves. If your scope doesn't include the threaded PTL, such as the NXS and SHV scopes, or you prefer a larger throw lever, our clamp on PTL will work perfectly. Machined from aluminum and anodized in the USA, the Clamp-On PTL requires no modification of the scope to use. Easily removed. This model of Clamp-on Power Throw Lever A289 is compatible with the following scopes: ATACR F2 Gen1, SHV 14x, 20x, SHV 10x, Illuminated Only. Since 1992, Nightforce has been creating the finest scopes that are used by professionals, hunters, and competitors. NightForce also provides a wide range of high-quality optics accessories