I had to replace the battery on my
X6 watch.
The cover was stuck and I was unable to open it with a 5¢ or a $1. I stripped the edges off the slot and I was no longer able to open it.
I guess the years of usage, and sweat somehow stuck the cap onto the ring and battery compartment.
I went to a distributor to see if they could repair it for me but they refused. When I was there, I purchased a battery kit for about 10$ anyway. The kit includes a new battery, new cover with gasket (O-ring) and a special tool.
The new cover and the tool are different from the old ones. They now have two small holes in the cover to insert the tool giving a better grip and prevent stripping.
To remove the old battery cover, I placed a bit of white paint on the ends of the two prongs of the new battery removal tool. I pressed the tool on the old battery cover stuck on my watch to mark the position where I would make the holes. After letting it dry, I used a small drill and with good lighting, I slowly and very carefully drilled two new holes. At the back of the battery cover it is only the battery, so I did not risk damaging the watch itself. I inserted the new tool and VOILA it finally opened.