I am very satisfied with my Neuro-Care Tens unit. It is a solid unit with a good user guide & added instructional pamphlet. I am pleasantly surprised at the tac & quality of the 4 included electrodes. The metal belt clip holds the unit pretty securely as well. I think this is a great unit at a reasonable price. I can understand why it is a bestseller. The free shipping was wonderful & although I live in rural Ontario I received my unit within four days. I am a very happy customer.