I need to send an email to my boss requesting a company cell phone. reasons why

I need to send an email to my boss requesting a company cell phone.
reasons why:
– work travel
– I find myself giving out my personal phone number when traveling to stay accessible with the teams.
– I rely on the team’s communication and don’t feel comfortable having to use my phone number each time.
– not always at my desk to answer my desk phone / missed calls
– I need accessibility when on the go, example emails, files, etc
I need the email to be convincing and to the point and it needs to be professional but not forced. I do have a good relationship with my boss.