Fit Cuffs – Bluetooth Device (LOP). Research has shown that this method (oscillatory / oscillometric blood pressure measurement), is a valid and reliable way to assess Limb Occlusion Pressure (LOP) compared to Handheld Doppler Ultrasound, relative to the golden standard i.e. invasive methods. Our +40 tests are showing a very good inter-rater reliability, by comparing LOP by this Bluetooth Device vs. LOP assessments by Handheld Doppler, as a variance of only 1-3%. This is a convenient and validated alternative to Handheld Dopplers for both the upper & lower body.