1、Functional Design: Provides extra focusing distance to increase focal length extension. Sometimes necessary for certain eyepiece or telescope camera combinations for focusing. 2、Extended Focusing Needed: Often requires more focusing distance when observing short distances on the ground with a telescope or using field flatteners, correctors, or reducer lenses. 3、Secure Connection: Equipped with 2 fixed screws to support connecting 2 inch telescope eyepieces and astrophotography filters, preventing damage to telescope accessories. 4、Universal Compatibility: Features front end with M48x0.75mm thread for use with 2 inch telescope eyepieces and astrophotography filters, ensuring a secure fit. 5、Sturdy Construction: Anodized black finish prevents unnecessary reflections. Made of solid aluminum alloy material for strength, durability, and wear resistance. Item Type: Eyepiece Extension Tube Material: Aluminum Alloy + Copper Interface Size: Approx. 2 inches /50.8mm Thread Size: M48x0.75mm Color: Black 1 x Extension Tube