My understanding is that test strips, with very few exceptions, are manufacturer and/or device specific. While SD Biosensor manufactures both SD Codefree and GlucoNavii Inc., the test strips for both devices appear to be different. If you look at the device specification table towards the bottom of this webpage from the manufacturer (https://www.sdbiosensor.com/product/product_view?product_no=246) you see that SD Codefree and GlucoNavii use different enzymes in the test strips. This most likely means they are not compatible.