Can this be worn in water

Of course, our magnetic bracelets for men are made of titanium and are completely waterproof and corrosion resistant.

Can you wear it in a pool or ocean

Yes, you can wear it in a pool but not sure about ocean. I wear it in the pool for water aerobics 4 days a week and it still looks new. They do recommend that you clean it with a toothbrush every so often and that does keep it looking nice. I use little toothpaste with the toothbrush.

Will this bracelet effect a watch or a cellphone?

Does not affect watches or phones。

I have very large wrists. What's the studying on these? And can I but extra links if needed?

Hi my friend, this bracelet's size is 15mm in width, 8.5" in length. if the length is not enough, please order two pieces, also there has a discount when you buy two pieces. thanks for your attention.