Abstract: A plug-in battery pack for an electrical tool includes a mechanical coding of a coding system for cooperation with a mechanical counterpart coding of the coding system associated with the electrical tool, in which the coding extends in the insertion direction of the battery pack. The coding has at least one recess that cooperates on opposite sides with at least one projection that is situated on the tool and constitutes the counterpart coding. The coding rib extends out from the wall of the recess.

Abstract: A water proof socket for outdoor light bulbs such as LED light bulbs which comprises a bulb cover housing the light bulb, the bulb cover housing having a neck portion for receiving the light bulb, internally threaded cylindrical member around the neck portion, and an externally threaded cylindrical base at the other end engaged in the internally threaded cylindrical portion. The bulb holder is attached to a seat member with a projecting rectangular member which has two holes with electrical contact passing through each hold. The rectangular member fits snugly in a cavity in said threaded member in said base and external wires pass through the base and makes contact with the internal electrical contacts.