going it alone

I'm new to open water swimming but I'm not much of a group joiner. I know everyone says don't swim alone but... Does anyone know of any devise that is made that will increase my visability to others in the water, and perhaps be used as an emergency flotation device if I get into trouble? I was searching on the internet and have seen the lifeguard cans and tubes but didn't know if there was anything made specifically for what I want it for. Any help will be greatly appreciated. Thanks