Try Esslinger.com or Ofrei.com.

 

I also have the surfboard and worry about how I am going to change the battery. To the OP, let us know if you get a tool, which one, and if it works! I am actually considering just biting the bullet and sending it to Bulova when the time comes to change the battery.

 

Problem solved. I tried the freezer for an hour as suggested elsewhere. Didn't work and the case back was so slick and cold nothing would attach. I looked at the Jaxa clone I have and tried the flat ended bits but the fit was imprecise and just asking to ruin the cover. Lol. Finally, I carefully wet a q-tip with alcohol and worked it around the edges of the case cover. I did this several times and used the dry end to clean off any gunk and debris. Using my rubber ball and watch in a case holder it opened without problems. Just gunked up after three years. Give it a try. Cheers.

 

https://www.watchuseek.com/posts/51280619/

 

I have a similar wrench from China that has bits that look the same. I'll tape up the back and give it a shot. Cheers and thanks.

 

I would try a caseback ball. That’s all I use for any watch.

 

Problem solved. I tried the freezer for an hour as suggested elsewhere. Didn't work and the case back was so slick and cold nothing would attach. I looked at the Jaxa clone I have and tried the flat ended bits but the fit was imprecise and just asking to ruin the cover. Lol. Finally, I carefully wet a q-tip with alcohol and worked it around the edges of the case cover. I did this several times and used the dry end to clean off any gunk and debris. Using my rubber ball and watch in a case holder it opened without problems. Just gunked up after three years. Give it a try. Cheers.