“Ringer” means that the t-shirt’s body is a different color than the elastic on the cuffs of the armholes and on the collar. e.g. the t-shirt body is white, but the cuffs and collar are navy. Sometimes the words “contrast trims” or “contrast piping” are used.

Here are some brands I found:

I really like the Velour Garments one because it’s 300gsm and made in Spain but it’s out of stock. Considering all the options I’m now leaning towards fruit of the loom, but I know it’s not going to be very well made, since it’s loom. I’ll maybe get one from them and then keep looking

Does anyone know any other options? The ones I listed are all t-shirts, but I wasn’t able to find a ringer tanktop anywhere.