A first rotatable locking type electrical connector having a polarizing sleeve with a detent and a first set of electrical contacts for electrically engaging a second rotatable locking type electrical connector having a complementary polarizing sleeve with a complementary detent and a second set of electrical contacts. In the preferred embodiments, the polarizing sleeve of the first electrical connectors has at least one key, preferably two keys, while the polarizing sleeve on the second electrical connector has a complementary slot or slots for receiving the key or keys of the first electrical connector. Each of the slot of the second electrical connector is arranged to receive a key of the first electrical connector so that the first and second electrical connectors can be coupled together by initial axial movement and subsequent rotational movement. Preferably, the detents are formed on the keys and within the slots for holding the electrical connectors against unintentional movement. Preferably, one of the detents is formed by alignment indicia, which indicates when the key and slot of the electrical connectors are properly aligned for axial movement and subsequent rotational movement.