Product Brief: More magnification for the existing eyepieces to see more details of the moon and bands of Jupiter clearly;the Datyson1.25 2x barlow lens is a better choice High quality and value barlow lens 2x gives a big magnification boost to any 1.25'' eyepiece;double the capacity of an existing set eyepieces at the cost of a single eyepiece 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 Main Points: Shortly height: 2.96 convenient to use and carry Free dust cover: Keeps lens clear easily with 2 pairs of dust cover 2x magnification factor with 1.25 interface: Doubles the magnification of any 1.25'' eyepiece Interface with M42x0.75 thread: With T/T2(M42x0.75mm) male thread for T/T2 connectors Quality aluminum stock and black anodized body: Precision machined;sturdy for a long term use With APO design: Offer a high quality observation without introducing additional chromatic aberration Multilayer HD broadband green film optical glass lens: Chromatic corrected;provide high transmittance;ensure clear;sharp views With safety undercut and brass compression ring: Ensure the eyepiece barrels will not be marred by the captive set screw Specification: Diameter:1.25/31.7mm Magnification factor:2x Lens material:pure optical glass lens Lens coating:FMC Sleeve material:Metal Thread interface:M42x0.75 pitch Length:2.9/7.5cm Weight:3.14oz/89g Package Include: 1 x Barlow lens 2 x dust cap