If you are new to Wacom, you should understand this issue because it is a constant source of confusion for people looking to buy a Wacom tablet, get help with a Wacom tablet, or buy a replacement pen for their Wacom tablet.
The problem: Wacom makes two very different devices with confusingly similar names:
"One by Wacom" refers to any of 2 pen tablets
One by Wacom Small (CTL-472)
One by Wacom medium (CTL-672)
"Wacom One" can refer to any of 5 drawing tablets in two generations
Wacom One GEN1 (DTC-133) - a pen display
Wacom One 12 GEN2 (DTC-121) - a pen display
Wacom One 13 touch GEN2 (DTH-134) - a pen display
Wacom One S GEN2 (CTC-4110WL) - a pen tablet
Wacom One M GEN2 (CTC-6110WL) - a pen tablet