This pulse ox has two features that you do not see on most machines. The plethysmograph and the perfusion index. The plethysmograph indicates the amt of bld flow detected and the perfusion index indicates the strength of your pulse. It is super easy to use and non-invasive. The batteries come with it and already installed. You simply insert your finger in to the measurement chamber..press the button and it measures your oxygen saturation and pulse in about 3-6 seconds. You can set parameters so it will beep if your saturation or pulse is low. It is comfortable to wear on your finger and stays in place well. The lanyard it comes with is made strong and a nice touch to carry it with you. The only con I can think of is it would be nice to have a pouch to put in in to throw it in your purse. It comes with very detailed instructions that are easy to read and follow. I like that you can change the display direction. Being a visiting nurse I have had many clients reading their pulse ox’s upside down ..thinking the display if facing them when in fact it is facing out. I tested this product against my own pulse ox that I carry in my bag and it is spot on. This would be perfect for anyone at home that needs to monitor their oxygen and/or pulse. You need to talk with your health care professional to get parameters of when to notify them and set the alarms to those parameters in the machine. I received this product free. All my reviews are based on my own experience and evaluation of the product so that others can benefit in finding quality products that meet their needs & expectations.