This is GSO's top quality / most powerful barlow made with precision in TAIWAN. The Barlow features an air-spaced, three-element, apo design with fully multicoated optics. The barlow comes with brass compression ring so that your eyepiece barrels are not marred by the captive set screw. The thread under the barlow accepts all 1.25" filters.

Barrel size = 1.25" (31.7mm)
Magnification factor = 5x
Weight = 3.8oz (108gm)
Total height = 3.46" (88mm)
End caps = 2
1.25" filter threads on bottom of barlow: No
Made in Taiwan