hi I received this mod this morning so I unpacked it and had a look first thing I noticed was the botton button would not unscrew and the lock also would not unscrew so at first I tried my rubber grips to free the locking ring but no luck it was really tight after a while of trying different methods I got my waterpump pliers out and covered the mod in kitchen towel to maybe not damage the mod but still I could not free the ring so it came to the point where I used 2 sets of water pump pliers and this freed the bottom button and the locking ring but at a cost of scratches on the mod this is where I should of stopped but I decided to polish the scratches off of the mod with some polish. I started to polish and bag suddenly I could see a copper colour so it's ruined my mod. Also the SS extender tube has a lot of movement and very little thread. If you want a magneto I would recommend the SS version FT sell as this is a lot better made I know because I own that model the only problem with the ss version is some people don't like the manufacture name on the middle tube but it's a lot better than this brass?(PLATE) version it is very cheaply made not impressed at all

the fit of this mod is poor I noticed was the bottom button would not move I unscrewed it and the lock was frozen took some time get it to work extender tube has a lot of movement and little to no thread i would not buy this mod

overall, I think that for the price this is an excellent buy, it is certainly not top quality but it IS an overall value. I had no issues with center tube movement (using both Sony VTC5 30A 2600 mAh Battery and TrustFire 1200 mAh 18350) with no problem. switch locking ring has locked up on me once since purchase, i sprayed a tiny bit of white lithium in there, no more worries. slight gap between deck and some 510 tanks (my Patriot RBA and Aspire Nautilus sit fine, Kanger Protanks 3 & Aero slightly raised).
those are the raw useage observations, take it as you will.

there any problem it works great (I not regret)

I have the original SMOK Magneto and this one is a good "looking" copy but does not even hit anywhere close as the original. I had to insert a kick into this for it to hit at 3.7 volts properly. I returned mine, its useless.