Inclusion Criteria:  Able to read, understand, and provide written, dated, informed consent prior to screening, and be likely to comply with study protocol, including independently complete study questionnaires and communicate with study personnel about AEs and other clinically important information. Women and men ≥ 18 years of age Self-reported bladder symptoms present ≥ 3 months Self-reported failed conservative care of behavioral modifications and/or oral medications On a stable dose of antimuscarinics/beta-3 agonists for ≥ 4 weeks, and willing to remain on the medication for the duration of the study OR discontinued antimuscarinics/beta-3 agonists for ≥ 2 weeks Ambulatory and able to use a toilet independently, without difficulty  Subject agrees not to start any new treatment for OAB (medication or otherwise) during the treatment and follow-up periods.  For Females Only:  If of child-bearing age and female, agree to practice approved birth-control methods (oral contraceptives, condom barrier, injection, diaphragm or cervical cap, vaginal contraceptive ring, IUD, implantable contraceptive, surgical sterilization (bilateral tubal ligation), vasectomized partner(s))  Exclusion Criteria:  Botox® use in bladder or pelvic floor muscles in the past year Subject weighs greater than 330 pounds Pulmonary insufficiency, defined as difficulty breathing and fatigue, especially during exercise; chest pain, such as squeezing, pressure of tightness; the sensation of rapid or irregular heartbeat (palpitations); swelling of the legs or feet; dizziness or fainting; and/or bluish discoloration of the nails and/or lips (cyanosis) Any condition that causes a lack of normal skin sensation to the pelvis, buttocks, and lower extremities Major metal implants such as: metal plates, screws, joint replacements, implanted cardiac pacemakers, drug pumps, neurostimulators, electronic implants, copper intrauterine devices, defibrillators, and metal implants in the pelvic area. Patients with other metal implants will be evaluated by the investigator for inclusion in the study. Subject has a piercing between the waist and knees and is not willing to remove it before each treatment Active urethral diverticula Known vesicoureteral reflux Currently healing from surgical procedures where muscle contraction may disrupt the healing process Subject has an active malignant tumor, in any location in the body. Skin cancers are permitted. Subject has used the BTL EMSELLA device previously Subject has urinary incontinence of neurogenic etiology, such as multiple sclerosis, spina bifida, Parkinson's, spinal cord injury, diabetic neuropathy, neurogenic bladder etc. Current urinary tract infection. If a subject has a confirmed symptomatic UTI at screening, per investigator's clinical judgment, they will be deferred from screening until treatment is completed, and may resume once symptoms have resolved Current use of neuromodulation therapy, including interstim and PTNS, for bladder symptoms within 3 months of screening visit (if past sacral/pudendal implant, must be explanted) Currently participating in an investigational study that may impact study results or previously received an investigational drug or treatment within 30 days of the Screening Visit  Current or history of any physical condition that, in the investigator's opinion, might put the subject at risk or interfere with study results interpretation  For Females Only:  Pregnant, or planning to become pregnant, at screening or anytime throughout the study period  Note: For the sake of preserving scientific integrity, one or more of the eligibility criteria have been left off the list posted while the trial is ongoing. A full list of eligibility criteria will be posted upon completion of the trial.