Inclusion Criteria:  Adult Type 2 Diabetes Mellitus ("T2D") Patients on Insulin Replacement therapy not administered via implanted pump well-managing p.r.n as defined by serum glucose ranging between 85 and 200 mg/dL and no more than 1 hypoglycemic or serious hypoglycemic event within the last 9 months. 25 and 75 years of age, inclusive. The subject is willing and able to read and understand the Subject Information Sheet and provide written informed consent. The subject has a body mass index (BMI) within 18-50 kg/m2. The subject is in otherwise good health as determined by medical history and physical examination. The subject's normal insulin dose ranges from between 10 to 200 IU per dose. The subject must agree to continue with daily serum glucose testing by means of a wearable blood glucose monitor for the pharmacodynamic assessments that the investigators have continuous access to via daily downloads. The subject is willing and able to comply with all testing and requirements defined in the protocol. The subject is willing and able to return to the study site for all visits.  Exclusion Criteria:  The subject has any relevant deviations from normal other than blood glucose in physical examination, electrocardiogram (ECG), or clinical laboratory tests, as evaluated by the investigator. The subject has had more than 2 hypoglycemic events in the last month. The subject's normal insulin dose is less than 10 and more than 200 IUs. Subjects receiving Insulin from an implanted or external insulin pump system. The subject has had a clinically significant illness or surgical procedure within 30 days preceding entry into this study. The subject has a history of significant neurological, hepatic, renal, endocrine, cardiovascular, gastrointestinal, pulmonary, or metabolic disease other than T2D. The subject has a known allergy or history of hypersensitivity to Human Insulin or similar modified Insulin compounds. The subject has used any prescription medication that may interfere with the evaluation of study medication. The subject has donated or lost a significant volume of blood (>450 mL) within four (4) weeks of the study, and subject's Hemoglobin concentration and hematocrit have not returned to within 5% of normal. The subject has a history of substance abuse or a current positive urine drug screen or urine alcohol test. Alcohol consumption greater than community norms (i.e. more than 21 standard drinks per week for males). Subjects who have received an investigational drug or have used an investigational device in the 30 days prior to study entry.