(a) Adherence IVR prototype with electronics module embedded in IVR elastomer circumference as used in in vitro simulation experiments. For clarity, the IVR is shown prior to sealing the circuit board and cylindrical battery pack in place using silicone adhesive. (b) Close-up of prototype electronics module. (c) Cutaway 3D model of adherence IVR prototype used in sheep study. The electronics module and battery are enclosed in a central compartment rather than sealed in the IVR circumference to allow access to the electronics during initial in vivo evaluation. A portion of the central compartment wall is removed in the drawing to expose the electronics module and battery.