I like that it is straight forward and does what a TENS machine system should do. No bells or whistles, but it works to relieve pain without medications. For those new to this machine, remember no TENS machine is a cure for the root problem. In my case, a bulging disc in my C5 In my neck that irritates the nerve causing, shoulder, shoulder blade, neck, arm pain. I have gone back to my pysio work to help posture and decompress the nerve. The specific movements/stretches provided by your trusted physiotherapist/chiropractic/doctor team will work wonders and heal when you put the work in. A TENS machine, basically is sending a signal to your brain faster than the signal from the nerve root can send a pain signal to the brain. Those electric impulses interrupt a pattern and the brain essentially receives the electrical signal before the pain. So it’s a natural pain blocker because the body is electric in nature with a lot of inner communications within the body. Yes, this unit costs more, but it really does the job meant to be done. Now there is debate that if the nerve /brain signal is interrupted enough over time, the nerve will relax more because there is no need to send a signal since there is bridge gap healing mechanism using the TENS machine. That debate is not important because, even if true, it does not correct the very root of the problem. It does something very important though. It does create a new pattern so that it can relax the pain to allow you to move, stretch, follow your specific approved rehab and exercise program and create a holistic approach to heal your body and create alignment, balance and health. Do not use this or any TENS machine if you have any metal and or pacemaker in your body. This treatment will harm you because it is carrying electrical current through the body. It is safe and in a low dosage, but does not mix well with any metal inorganic surgically placed structures in your body. Otherwise, use this and add it to your full healing approach. It should take your acute pain away more effectively than pain killers. That has been my experience. The seller did send everything as promised packaged really well. Delivered on time and high praise for the seller. Good luck and happy healing to all of us.