It's easy to use;simply insert the eyepiece into 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:
2x magnification 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

2 element one group optical glass:
High quality observation without introducing additional chromatic aberration

Multilayer HD broadband green film optical glass lens:
Chromatic corrected;high transmittance to achive clear;sharp views

Safety undercut and brass compression ring:
The eyepiece barrels will not be marred by the captive set screw

Common sense:
Barlow lens' role is not just to improve the image quality;it's also play an important role of viewing comfortable

Even a well made Barlow will little damage on the imaging quality

When the Barlow lens and eyepiece using together;if the magnification is higher than the maximum effective magnification of the telescope itself;the Barlow lens
observation effect appears nearly zero or blurred In order to reduce the influence of imaging 2x and 3x is a better choice

Specification:
Diameter:1.25"/31.7mm
Magnification factor:2x
Lens material:pure optical glass lens
Lens coating:multilayer HD broadband green film
Sleeve material:metal
Thread interface:M42x0.75
Length:2.9"/7.5cm
Weight:3.14oz/89g

Package Include:
1xBarlow lens
2xdust caps