You don't need a barlow with this eye-piece, nor Powermate.... Reason I am selling is I no longer have my F6 scope.
Thats 268 power on a MN56 scope!........nice. Thats 54 times the aperature for a f6 scope or 59 times the aperature on a F6.5...or 45 times the aperature on a F5 scope...(typically a Newt anyway). Perfect for the (Dawes Limit) viewing on your scope....I have had a Klee, a Celestron Ultima, and a Powermate, a Meade APO..and this blows them all away. (It has less glass and more eye relief because of the Ed element)Closest to it was a 2.5 Powermate with a research grade 7mm ortho, but then you have about $300 invested. For two powers you would have $400 invested, which would buy you a couple of LE's new. I have also tried it against a Radian (made in China :(....). This is Tak Quality at a reasonable price. They sell for $200 new...save $40 for $160 plus shipping.