XFFCSEC 18650 Battery Holder - 3 Slot Plastic Case for 3.7V Flat Top Batteries | Secure Power Supply for Flashlights, DIY Electronics & Solar Projects | Pack of 10 Black Plastic Cell Holders with Pins

Very cheap, battery connections using what appears to be a very ductile pot metal. I bought these to run 6x 18650’s in parallel for a Meshtastic node. First time using, I placed batteries in holders. Batteries were brand new and had no external damage. Started to smell burning and felt batteries and one was extremely hot. Began rapidly pulling cells out of this holder when one proceeded to weld itself to the positive end of the battery. At that point a tiny flame started and I just had to get those cells out so I ripped the welded cell out of the box where it then takes every battery contact point along with it. Cheap Chinese made garbage.