I have most which are M30 x 1.5 mm which I have fitted eQ-3 heads on them so programmed for times of day in use, but I have 4 odd ones which seem to be a larger thread. They are designed to adjust for different pin travel and have a fault display if there is a problem.
But with non electronic the pin travel needs to be correct, mine cost £15 each in 2019, pre-brexit, I had to buy on internet, and got the bluetooth version.
There is also the Terrier i30 which is non linked, but most of the electronic versions are more expensive, and link to a hub or wall thermostat to tell boiler to fire up when required.
Batteries last around 2 years, I change every year to be on the safe side. I also use these
also not electrical connected to boiler, but are internet connected, also they don't report if pin travel is OK, and you can't manually set them, yes they have geofencing, but the anti hysteresis software is OTT so don't really work very well with geofencing, and far more expensive, think I paid £75 for a pair, they had two screw threads, I used the M30 1.5mm and also needed a hub, so another £50 only advantage over the other one was they show both current and target temperatures so this
makes it easy to set lock shield valve. And I look at the temperature of the room in summer when out to decide if to turn on AC before I return. But all in all the cheap one is better. The cheap one even has window open detection, so when we unload food in the kitchen, it turns off heating in kitchen while we do it.
The two cheap ones come with adaptors
seen here with Terrier i30. There were not so many options with more expensive version.
It seems the Drayton Wiser is the crem de crem at moment with algorithms to work out when to heat room so warm at time set, there is also the Honeywell EvoHome with a central display to adjust them
but these are as one would expect more expensive, the eQ-3 was nearly the same price as the mechanical so seemed no brainer, fit the electronic. But at £70 a head for some, not so sure worth the money.