I have been slowly accumulating circle T ortho to compliment my T6 Naglers and I found this unbranded 4mm ortho on eBay the other day for a reasonable price and bought it. I didn't see the typical circle T sticker on it, but I was hoping it was on the other side or circle T was stamped on the barrel. Unfortunately no sticker and the barrel has no makers mark stamped in it. Fortunately it is in great condition besides some slight wear on the barrel.
It looks identical in design, the only difference I have noticed is that the 4mm volcano top has a glossy finish compared to the 9mm, 12.5mm, and 18mm I already own.
I think this one is circle T because it is just so similar. I think that the glossy finish simply means it was made during a separate batch, from what I know Tani was in business for a while, and the sticker either fell off or was taken off by a previous owner, but these are just my best guesses. Any way to confirm that an unbranded ortho is a circle T besides the sticker or makers mark? I know that there were some similar orthos that were not circle T, https://www.cloudyni...-glass-to-tani/ and I am trying to complete a set of unbranded circle T.
The last picture is the underside of the 4mm ortho next to the 9mm circle T.