Hello . The xARM has changed a lot since Feb that was displayed in Munich, at the time it was at a proto testing mode.
The new xARM is now shipping and info and specs can be found here. http://www.flowcine.com/home/105-xarm.html
About the spring cores. They are indeed made with multible ruber tubes in various configurations.
The stated tange of each core is specified on it and it covers a range of around 6kgr, but bare in mind that all cores are over rated at both ends, so you can easily down tune each core 1.5 kgr or uptune it 1.5kgr and have a more expamted range . The specification rated on each core is the limits you get the very best of its performance.
The xARM is silky smooth , rigid with SS socket blocks and Ti arm posts, it has a big boom range of 780mm or 30.7 inch, and it weights no matter what spring core you are using at 4.8 Kgr thats with the stainless steel socket block.
the responce is excellent specially in very slow step moves , and effortless booming the arm up or down.
Any questions you migh thave I will be glad to answer them here or in my mail email@example.com.
The xARM comes all with 3 different spring cores covering a range u to 29 kgr as standard and you can also get optional spring cores for lower weight rigs with min 8kgr.IThe package also includes a front mount socket block , as well as a back mount solid SS socket block, all 3 different tiffen and pro-gpi titanium arm posts and all tools all in a nice pelican air case.More accessories are on the make like low mode brack, a new socket block drop down adapter , high post , etc
You can change both spring cores in under 2 minutes some quick videos I made here .https://www.youtube.com/watch?v=O-9rPUfoK1U&t=18s
also tuning procedure here
we were at both Cinegear 2018 and the stabilizing expo and next show will be IBC 2018. Feel free to come fly the xARM with our cinelive sled more than welcome.