Item Type: Lens Extension Tubes <br>Material: Aluminum Alloy <br>Color: Black <br>Product Size: Approx.3mm / 0.12in, 5mm / 0.20in, 7mm / 0.28in, 10mm / 0.39in, 15mm / 0.59in, 20mm / 0.79in, 30mm / 1.18in, 12mm / 0.47in <br>Application: Extend the focal length of the primary mirror of the astronomical telescope <br>Extinction Treatment: Internal with extinction thread <br>Interface Female Thread Specification: M42x0.75mm <br>Interface Male Thread Specification: M42x0.75mm<br>1、Easy to install, perfect replacement for the old or damaged one, reliable to use. <br>2、Made from high quality aluminum alloy, which is wear?resistant and not easy to damage. <br>3、Using fine workmanship CNC technology, the accuracy is higher, durable. <br>4、The female thread specification of the interface is M42x0.75mm, the male threadspecification is M42x0.75mm. <br>5、Various sizes of 3mm/5mm/7mm/10mm/12mm/15mm/20mm/30mm are suitable for different models.1. Please allow 1?2in error due to manual measurement. Thanks for your understanding. <br>2. Monitors are not calibrated same, item color displayed in photos may be showing slightly different from the real object. Please take the real one as standard.<p>1 x 3mm Extension Tube</p><p>1 x 5mm Extension Tube</p><p>1 x 7mm Extension Tube</p><p>1 x 10mm Extension Tube</p><p>1 x 12mm Extension Tube</p><p>1 x 15mm Extension Tube</p><p>1 x 20mm Extension Tube</p><p>1 x 30mm Extension Tube</p>