The Sony Koriyama factory (“K” in lower left of the two lines of printing) has changed or added a different appearing top cap crimp to its VTC5A cell. This cell seems to perform the same (more testing to be done though) but has a wider ring crimping tool mark ring near its top. See the photos for an example. These fat ring cells are also made in the Singapore factory, indicated by a G or SG in the lower left corner of the two lines of printing on the cell. Please note... - While there are genuine Sony VTC5A’s with this “fat ring” that does NOT mean every VTC5A you see with a fat ring is genuine. - The counterfeiters might have found fakes with fat rings to use. We can only say that there are genuine Sony VTC5A’s with the fat ring in production. - If you have a VTC5A with a thinner ring this does NOT mean yours is definitely a fake. It might be anyway but there are huge numbers of genuine VTC5A’s out there with the narrower ring. - To help determine if your VTC, any of of them, is a fake or not carefully unwrap them. If the black top insulating ring is glued on it is definitely a fake. - If the black top insulating ring is not glued on it could be genuine. A loose top ring does not guarantee it’s an authentic Sony though as some fakes are not gluing on the ring now. - Look for the two dimples on the top of the cell as shown in the photos. All VTC’s have these. If your cells do not then they are not genuine Sony VTC cells. - If your cells do have the dimples then they are genuine VTC’s but there is no way to tell which. Some fake VTC5A’s have used other VTC’s. - The wrap, wrap code, and printing are unreliable indicators of whether they are genuine or not due to their variability between factories and over time. - Please don’t send me pictures of your cells to have me authenticate them. I am unable to. Use the checks I’ve described here. If you are still unsure and are concerned they might be fakes then speak to the vendor you purchased them from.