The Silverback SMR is the MetrologyWorks version of the classic Laser Tracker SMR that uses 3 panels of glass that are assembled into an optic and then that optic is assembled into the SMR. These SMR s are known for their entry level price as well as their overcoated optic that allows for protection from the elements and the ability to be cleaned frequently. Metrologyworks uses a proprietary design that includes an isolation core that adds stability and durability to the piece while also allowing the optic to be used in connection with the MetrologyWorks proprietary centering process that can yield very high centering accuracy including High accuracy SMR s. Each SMR includes a protective ring which helps to block stray light while also allowing you to attach a lanyard to it. The Laser Tracker SMR protective ring is removable for unique applications where you may want to increase the entry angle. The glass panel SMR s have been around since the invention of the Laser Tracker and a staple in many tracker tooling kits. The only drawback to the Silverback SMR is that they do use a glass reflector that is fragile and if the SMR is dropped can shatter. If you are using the SMR in an application where dropping the SMR is a concern we encourage you to look at either our Rhino Series laser tracker SMR s or our Solid laser tracker SMR s.