Total of 40 PCS, 2 inches X 4 inches. Flexible, comfortable, and easy to apply - sticks on lasting comfort and easy to peel off. Coated with long lasting reliable gel - you can be assured that you will receive a high-quality product. Can be applied to any contour of the human body - conforms to your body. All Electrodes are compatible with all TENS and EMS units we sell and most other units on the market Use for TENS, IF, muscle stimulator and more. It is not for ECG and EKG (Electrocardiogram Machines which are heart check machines) The White Cloth series of electrode pads are high quality, premium TENS Electrodes made with high quality adhesive for reusability. These TENS Unit Electrodes are professional quality and very popular with Healthcare practitioners for in-house use with their professional electrotherapy devices. They also make a preferred choice for personal use TENS Unit. These TENS Electrodes offers the highest quality of reusable gel on the market. Since the Electrode Pads are pre-gelled, simply place them on the area, and when finished, place them back on the electrode pad (included). The better you care for the electrodes, the longer they will last.