After 14 years, ACR won't provide replacements. It was rated through last December. I replaced with a new ACR that has an integral GPS output.
I also have a PLB from ACR (which I got for single handing). I wear it with my inflatable PFD and harness my wet gear, if I'm alone or the weather gets rough. This smaller ACR PLB unit has a "hear I am" capacity to send 'okay' messages, in addition to the emergency purpose.
I've been on boats where others brought their own and sometimes wear them too.
There is a neat AIS unit that can be used as a PLB that is just out.
At somepoint we will be like the Borg. ;^))))