Surface acoustic waves (SAWs) are an alternative source of external physical stimuli for water-in-oil droplet manipulations. SAWs are formed when an electronic waveform, usually in the MHz frequency domain, is transduced into mechanical energy through metal electrodes deposited onto a piezoelectric substrate. The metal electrodes are commonly deposited with a geometry that creates interdigitated transducers (IDTs) to broadcast the electronic waveform along finger-pairs that convert the oscillating signal into mechanical vibrations across the substrate. Typically, the substrate thickness and distance between the finger-pairs determines the resonance frequency. Devices that generate SAWs are designed to function with minimal energy losses by propagating the SAW across substrate surfaces exposed to air. . SAWs applied to an air-to-fluid interface refract into the fluid leading to compressional waves that enable manipulation of droplets via local interface deformations . The refraction of SAWs at such interfaces is usually associated with strong losses in the waveform amplitude, which has been exploited when, for example, heat generation is a desired function . Among other characteristics important for optimizing the manipulation of fluids with sound, the acoustic streaming velocity is influenced by the applied waveform frequency and amplitude as well as the type and geometry of the IDT producing the signal.