Astro-Tech 10mm T-thread spacer ring for DSLR and CCD imaging with 42mm Threads

This Astro-Tech 10mm T-thread spacer ring has standard male and female T-threads (42mm x 0.75mm). It is used in prime focus astrophotography to position a DSLR or CCD camera's focal plane the correct distance from a focal reducer, field flattener, or other imaging accessory for optimum image quality. The spacer weighs only 0.5 ounces and is precision-machined from aluminum and anodized black for good looks and durability. It has matte black internal anti-reflection threads for maximum contrast. It can be used alone or in combination with other spacers to achieve the correct component spacing.