tellmemore145

As tgsovlerkhgsel said, they're not the classic style of jammer. That kind of thing is called a "smart jammer". And if you built that exact kind of functionality into a device and sold it (vs. just allowing the customer to code it themselves, like they could on any wifi device), you are probably committing a felony by manufacturing and selling a signal jammer.

Can you link to one of these watches? If they're being sold with that purpose-build functionality, that's probably a federal crime. You cannot make, possess, or operate a signal jammer in the US.