Multi-Height Set of Pictinny Rails for AR-15 Risers For Finding and Setting the Correct Sight/Optics Height Calculating total optic height above a receiver rail is difficult due to varying specifications from a variety of ring manufacturers. The set consists of six risers/rails varying by 1/10th inch increments; .5", .6", .7", .8", .9" and 1"... Providing the height you need for perfect alignment. Examples of Use - Optimal clearance for the objective lens of your scope or, alignment of multiple sights (optics, red dots, magnifiers, and iron sights). Being able to select a riser that fits a particular application allows for perfect alignment... Of a scope and forward mounted Night Vision Device (NVD) for example. Configuring a custom riser height can enhance the performance of many fixed mount (no ring) optics as well. Proper height positioning of optics and other rail mounted accessories can also be critical to obtaining maximum accuracy. Durable CNC machined aluminum construction with anodized finish ensures precision fit and function. Each riser is 5.75" in length and incorporates three T15 fasteners for absolute maximum mounting strength. A second set of fasteners is included so two of the six risers can be utilized independently. Set includes six risers in 1/10th inch height increments.