M23.2 and M27.5 Fixed Tubes and Retaining Rings

TECHSPEC® M23.2 and M27.5 Fixed Tubes and Retaining Rings feature black anodized aluminum construction. The fixed extension tubes are ideal for covering portions of the cage system. Each fixed extension tube is designed to fit within the inner diameter of a cage system plate, and feature either M23.2 x 0.75 or M27.5 x 0.75 female threading throughout the entire length of the tube. TECHSPEC® M23.2 and M27.5 Fixed Tubes and Retaining Rings, when paired correctly, can be used to secure optics within the extension tube, while adjustable length tubes and thread adapters can be used to connect fixed extension tubes for building customized optical assemblies.  
M23.2 and M27.5 Tube System Retaining Rings feature a thin, 3mm thickness. They are sold in pairs and are ideal for securing optics within extension tubes. Each retaining ring features an optic shelf which centers the optic within when sandwiched between retaining ring pairs. 

Accessories

#85-582 threads into a M23.2 x 0.75 standard tube to easily mount a plate beamsplitter. #85-539 fits within the inner diameter of cage system plates; it also threads into a M23.2 x 0.75 standard tube.