This is a SM100J 100 watt transformer. It is black in color to radiate off the excess amount of heat. The internal built is of fine quality that can take in a lot of load. Being small in size it can be carried anywhere along with the personal things. It can convert 117 volts down to 100 volts. It has sockets that can be used with multiple numbers of plugs. This transformer is mainly useful with Japanese products. Though products from Japan are as highly valued as US products, they use different voltage. As a result a small transformer is required to convert the current that is best for the appliance.