Subjects in the upper arm group will have a sensor of the CGM System inserted on each arm (left and right upper arm). Subjects in the abdomen group will have 2 sensors inserted, one on each side of the abdomen (left and right abdomen) The sensors will be placed for 29 days. After sensor insertion, the CGM system should be calibrated with capillary blood glucose readings from a self-monitoring blood glucose meter。

Inclusion Criteria:

1. Type 1 or 2 diabetes mellitus
2. Male or female age ≥ 18 years old and ≤ 70 years old
3. Willingness to adopt measures to prevent water coming into contact with the device sensor (e.g. abstain from swimming, sauna, avoid hitting the sensor with direct jets of water)
4. Ability to communicate with the investigators, able to operate medical device after training and comply with the testing procedures outlined in this protocol (including, but not limited to, willing to wear the continuous glucose monitor and testing capillary blood glucose)
5. Subjects who show understanding of the study procedures and willing to sign a written informed consent form.

Exclusion Criteria:

1. Hospitalization due to diabetic ketoacidosis or severe hypoglycemia, within 3 months prior to screening
2. HbA1c >13% or urine ketone 3+
3. Use of pacemaker
4. Body Mass Index (BMI) ≤18.0kg/m2
5. Extensive skin changes/diseases that preclude wearing the required number of devices on normal skin at the proposed application sites, i.e. upper arm or abdomen (e.g., extensive psoriasis, recent burns or severe sunburn, extensive eczema, extensive scarring, extensive tattoos, dermatitis herpetiformis)
6. Any psychiatric disease such as depression or anxiety
7. Any severe hepatic, renal, cardiac, cerebral, respiratory or neurological diseases (e.g. serum ALT, AST, Creatinine level ≥3 times the upper limit of normal)
8. Has a MRI scan, CT scan or other procedure requiring the subject be under strong magnetic or electromagnetic environment, scheduled during the proposed study participation
9. Blood loss >400ml in the past 3 months (including blood donation)
10. Have a known allergy to medical-grade adhesives, or known hypersensitivity to any of the products used in the study
11. Difficulty in sampling venous blood or cannot tolerate venipuncture
12. Participated in other investigational studies in the past 3 months
13. Currently pregnant or lactating women, or positive pregnancy test
14. Any condition that, in the opinion of the investigator, renders the subject not suitable for the study.