On December 14, 1987, two bombs exploded in the centre of Dublin, killing a young woman and wounding four people.
The two bombs were both made by a single company, Dwyer Instruments Inc.
The company, based in New York, made about 3,000 devices, many of them in small metal boxes with a built-in fuse.
They are not as easily identifiable as other devices such as bombs or remote-controlled vehicles.
They were used in a variety of ways, from toaster ovens to the use of mobile phones.
In the early 1980s, the Irish Department of Agriculture published an instrument flying hand book to help people who were trying to identify instruments used in bomb attacks.
In it, it states that devices which could be used in an improvised explosive device (IED) attack include a bomb, a car bomb, explosives, a rocket or small weapon.
At the time, the bomb-making industry was booming.
In 1987, a report by the Irish Government said there were about 4,500 bomb-maker jobs across the country, and about 5,000 bomb-makers were employed in the United States, according to the Bureau of Industry and Economic Research.
When asked about the Dublin bomb, Déjà Vu spokesperson Sean MacQuarrie told the Irish Times that the company had not made a device for an IED attack, and it would be difficult to identify the exact design because it was manufactured in the USA.
He said that the Dublin bombs were made by an Italian company called Dwyer Instrument.
He said that there were other devices used in improvised explosive devices.
Dwyer Instrument is a company based in the US, and is also based in France.
Irish Independent journalist and author, Kevin McPherson, said in an interview that he found it hard to believe that Dwyer would have made an IIED bomb.
He told the Independent that he has heard from some people who have used Dwyer instruments in bomb blasts in the past.
“It is extremely unlikely that Dwyers would have produced an IUD, let alone one with a fuse,” he said.
It is unclear if Dwyer has made a bomb for an attack on the US.
In an email to The Irish Examiner, Dwyers spokesperson told the publication that it did not comment on individual products.
The Dublin explosion was not the first IED bomb attack in Ireland, but it was the first one to use a device made by Dwyer.
More than a dozen IEDs have been launched since January 2016.