It was supposed to make everyone's life easier and better.
Already available in parts of Irish cities, 5G can turn your phone into an ultra high-speed broadband device. But it is currently being cited as an excuse to attack telecoms masts by fringe activists touting conspiracy theories that range from Covid-19 to cancer.
This newspaper has covered the damage in depth over the last week: hundreds of masts around Europe vandalised and at least two attacks here, the most serious being a suspected arson attempt to an Eir mast in Letterkenny on Easter Sunday.
Yesterday, Facebook reacted to Irish Independent reports of Irish anti-5G comments threatening to "burn down" masts and advising on which kinds of weapons can "sort out" telecoms maintenance crews.
The social media giant took down such comments from the Stop 5G Letterkenny group page and has promised to do more. Some of the remarks taken down by Facebook were made days before the attack on the Eir mast in Letterkenny.
Why is this sabotage happening?
The answer lies in a mixture of extreme conspiracy theories and decades-old suspicions of health threats that are based on largely debunked theories.
At the extreme end, some Irish anti-5G commenters have suggested the current Covid-19 pandemic lockdown may have been "pre-planned" to allow for an obstacle-free 5G rollout.
A more widely held view among activists is that radiation from phones, and phone towers, can be bad for human health. This latter fear is a powerful political agent in some Irish county councils. Five councils - Clare, Wexford, Wicklow, Sligo and Leitrim - have passed resolutions calling for a halt to 5G rollouts on health grounds.
Yet scientists and regulators have repeatedly said 5G differs little from current 3G or 4G mobile signals when it comes to radiation levels. Their voices are added to those of Irish and European safety authorities, who say 5G radio waves are well within what is considered safe to human health.
From a medical perspective, the issue appears to be settled: 3G, 4G and 5G signals are not dangerous to human health.
Any claimed evidence to the contrary tends to be sourced from the outer fringes of the scientific community or based on isolated incidents of political officials pausing a 5G rollout for further testing.
In researching this issue over the last year, I've attended regional anti-5G protest meetings. When I put it to organisers that 5G is deemed to be within safety limits, organisers often reply that regulatory and scientific bodies are either lazy, corrupt or haven't tested thoroughly enough.
Alternatively, they claim even if the safety and regulatory bodies are bona fide, the technology is still too recent for any definitive long-term studies.
This point is also rejected by authorities, who cite successive studies over 20 years. Echoes of this last argument can be heard on prime-time television.
Earlier this week, Eamonn Holmes, the Northern Irish anchorman of the ITV 'This Morning' programme, was forced to apologise after suggesting mainstream media was wrongly "slapping down" 5G healthscare stories because they "suited a state narrative".
On unproven fears linking 5G to health problems, Mr Holmes claimed the mainstream media "does not know that they're not true". Although he later acknowledged "there is no connection" between Covid-19 and 5G, he left the door ajar on the issue of whether 5G might still be bad for your health, adding "many people are rightly concerned and are looking for answers and that's simply what I was trying to do".
Other than talk of radiation and safety, how is 5G different to 4G or 3G? Why is it called 5G?
'G' stands for 'generation'. '5G' simply means 'fifth generation' in mobile phone technology evolution.
On your smartphone's 'signal bar' symbol, you'll typically see a number, followed by the letter 'G'.
If it's 3, that means you only have a basic signal - good enough for calls and basic online activities like a Google search or a WhatsApp message, but not enough for a YouTube video.
If you see '4G', your phone should be able to run a Netflix film on its screen, as well as other online activities.
The idea with 5G is that your phone or laptop will be able to run much faster online applications, like ultra high-definition video or games. Or it will be able to connect other things, like a car or medical equipment.
Only two operators in Ireland offer a 5G service: Eir and Vodafone. And because they are only six months into the rollout process, it remains confined to parts of cities.
Three, Ireland's second-largest mobile operator, is yet to launch.
Most new flagship phones have 5G capability, although Apple won't launch its first 5G iPhone until this September.
In time, the operators intend to roll it out as widely as economically possible. Rural areas protesting against it may find themselves having the worst mobile coverage in years to come.