It is that, but that model does not integrate with SmartThings.
As far as why they didn’t Make a U.K. model, very few companies make smoke sensors for both the U.K. and US because the differences go way beyond voltage and both regions have a long certification process to make sure their requirements are met.
Even the sound patterns are different. The UK requires a long tone, rising in volume with each repetition. The US requires a “bee bop” two note tone with equal volume throughout each repetition, but a differing volume for the two notes. There are many other differences as well.
We have previously discussed this in the forum with regard to why Fibaro, an EU company, doesn’t make a US version of their smoke sensor. They announced a US version about 5 years ago, but never did end up bringing it market because of all the regulatory issues.