This one compared to the other which I liked a lot is the numbers are larger and brighter. Where with the Sm-150 the red is too blended into the black background. Other then that I love these , I have a husband that has seizures and asthma as, well as I have cold and tachycardia which these are great to have with us at all times. My 7 year old daughter has pulmonary stenosis so we use these to monitor her heart rate. I am very greatful to be able to review these. Checkout below the videos on how these amazing devices work.