More magnification for the existing eyepieces to details of the moon and bands of Jupiter clearly;the Datyson1.25 inch 2x barlow lens is a It's easy to use;simply insert the eyepiece of choice into the barlow lens then insert the barlow lens into the scope The barlow lens also could provide more magnification without reducing the exit hole on the eyepiece;it keeps a comfortable observation with wide view dust cover:Keeps lens clear easily with 2 pairs of dust cover Quality aluminum stock and black anodized body:Precision machined;sturdy for a long term use With an 3 elements design:Offer a high quality observation without introducing additional chromatic aberration Multilayer HD broadband green film optical glass lens:Chromatic corrected;provide high transmittance; clear;sharp views With safety undercut and brass compression ring: the eyepiece barrels will not be marred by the captive set screw Diameter:1.25 inch /31.7mm Magnification factor:2x Lens material:pure optical glass lens Lens coating: Thread interface:M42x0.75 pitch Length:2.9 inch/7.5cm Weight:3.14oz/89g Type:Monocular Colour:Black Material:aluminum alloy Package Contents: 1* Barlow lens 1* dust cap Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.