B Series Lens Mount Barrels are used for mounting simple lenses and achromatic doublet lenses to protect them from possible damage. These lens barrels can be integrated into an optical system by mounting them in SB or CB Series Lens Barrel Holders. The lens barrels consist of a threaded body and a retaining ring; when screwed together, the lens is securely held in place. For thick lenses, the retaining ring is reversible. Two or more lens barrels can be threaded end-to-end to construct simple optical systems.Lens barrels for 6.35 and 12.7 mm diameter lenses have a M20.25 RMS thread on the outside diameter for mounting into B18 Series Lens Mount Barrels. The B20-RMS Focusing Barrel allows axial translation of an optic over 5 mm by turning the knurled knob. The B25.4-RT Rotation Barrel allows 360° rotation of an optic with 2° graduations. The B25.4-F Barrel allows 25.4 mm diameter mirrors or lenses to be mounted to M20.25 RMS-threaded components. SB Series Lens Barrel Holders are available to mount all sizes of B Series Lens Mount Barrels or mirrors on a post or in the X26 rail system. SB19 is compatible with B25.4 . The standard optical axis height for SB19 is 19.5 mm. These holders should be mounted to UMR5 Series Linear Stages on top of CN26 Carriers to maintain the normal 40 mm optical axis height of the X26 rail system. The SB32 accepts the 18 to 50.8 mm size barrels. It can be directly fixed to the CN26 Carriers and will have a 40 mm center height above the rail. SB19 and SB32 are delivered with three screws, three washers, and a retaining ring that permits direct assembly of mirrors and other optics.CB Series Lens Barrel Holders provide a means of holding B Series Lens Mount Barrels for up to 50.8 mm diameter lenses on the X26 rail system at an optical axis height of 40 mm above the rail. The CB26 with smaller thread diameter have a 14 mm diameter hole to enable the micrometer on a linear stage to pass through, allowing components to be mounted closer together.