Thank you very much for viewing. Please check the manufacturer's website for detailed specifications. This is a set of 4 units. The main units only, and there are no accessories such as manuals. Initialized by simultaneously pressing three external buttons and then turning the power button on the back on again. Please consider these as used items for practical use only, as there are stains, label maker residue, marks, magic marker marks, missing rubber feet, etc. (The condition varies for each of the 4 units). No major damage was found on the bodies. Please note that it may take some time to respond to questions.