Uranoport piggyback resolving Barlow. 1.5x nominal. It varies a bit because you thread this onto eyepieces like a filter. Recommended for Plossls, Abbe orthos, Kellners, RKEs, Konigs, and the like. (Not generally for eyepieces with "built-in Barlows" because there may not be room for it to thread on.) You know you want to try it. I did, but I only have one eyepiece to use it with. They're $69.95 new.
$50 shipped in North America. (SOLD)
PayPal okay with no extra charge.