Well known, and very good Barlow 3 optical elements made in Japan. It's also available under different brands (Antares, Parks Gold Barlow, Orion Shorty Plus etc). It's one of those short-design Barlows and will usually give bit more magnification than 2x. In case of my camera it gave around 2.5x magnification increase. No chromatic aberration, reflections or other problems noticed. Also didn't spot any vignetting problems with 20 mm Erfle eyepiece.
