For those wondering about the model 'B' versions of the Ex range, there is no real mystery here.
The 'B' model is intended to meet the needs of building surveyors who carry out thermal audits of a structure. This is a fiercely competitive market for FLIR so a cost reduction may increase their hold over such a lucrative customer base. Thermal audits are a significant market in this modern eco friendly world in which we live

NEC AVIO released the F30 thermal compact camera in a version specified for the building thermal audit community. It had a smaller temperature range but apparently a greater temperature difference resolution as well. Such is important when viewing walls for minor thermal anomalies. NEC named the version F30
s and it was also sold by Mikron under the name Mikroshot 'B' for 'Building' version. The camera sold at a relatively competitive price and was designed to fit into a surveyors pocket. Temp range topped out at 100 C but it also has the advantage of manual focus and decent FOV. Thermal range and amazing measurement accuracy are not paramount in building survey work
The lens is a clever design in that it is manual focus at close range and effectively fixed focus at long range so no need to fiddle with focus all the time on a building survey.
I have examples of the Mikron B in my collection but apart from taking one apart I have not had time to play with them. I will have to see what happens when one is pointed at a target hotter then 100 C. Very nice little camera though and perfect for field photography of wildlife as that tends to run cooler than 100 C

I attach the data sheets for further info.
The FLIR Ex 'B' appears little different in terms of the intended market and the lower price may appeal to those who do not need amazing accuracy or temp range. It should be remembered that where accuracy is concerned anything specified tighter than +-2% is really only for laboratory experimentation as target emissivity variance destroys absolute accuracy anyway

Aurora