All users have to do is carry one, and the battery lasts up to nine months without needing a recharge - something one expert said had "stunned" him.
The government agency which developed the devices acknowledges that the Tokens - and technology in general - aren't "a silver bullet", but should augment human contact-tracers' efforts.
The first to receive the devices are thousands of vulnerable elderly people who don't own smartphones.
To do so, they had to provide their national ID and phone numbers - TraceTogether app users recently had to start doing likewise.
If dongle users test positive for the disease, they have to hand their device to the Ministry of Health because - unlike the app - they cannot transmit data over the internet.
Human contact-tracers will then use the logs to identify and advise others who might have been infected.
"It's very boring in what it does, which is why I think it's a good design," says hardware developer Sean Cross.
He was one of four experts invited to inspect one of the devices before they launched. The group was shown all its components but were not allowed to turn it on.
"It can correlate who you'd been with, who you've infected and, crucially, who may have infected you," Mr Cross adds.