Safety 1st monitors pick up the slightest of sounds. I can go about my house work and feel confident about my baby sleeping in his room and not having to stop and check on him all of the time. We live in a bi-level, so I am always going up and down the stairs doing laundry or other chres, I don't have time to sit by my baby's door to isten for him to wake up from his nap. The safety 1st monitor gives me freedom to roam around my house, The belt clip makes it conveinient to carry with me at all times or I can plug it in when I am on my computor or in another stationary place.