Make sure this fits by entering your model number. Support Two Modes: 1. Spot Check-> Read your oxygen level in real time whenever needed without recording data 2. Continuous Tracking -> Record data second by second over time for later analysis and report. Stand-alone oxygen monitor with 72 hours built-in memory that you don’t need a smartphone to make it work. Wear it to sleep and take it off to sync in the morning. Settings (alarm threshold, mode switch, memory clearance) can be done on the device itself without connecting to app.