A Tamiya connector is a type of DC power connector,commonly used on radio-controlled model vehicle battery packs and chargers. They are also commonly used on airsoft guns.
The usual wiring has the positive (red) wire running to the terminal with a square profile, and the negative (black) wire running to the half-circle, half-square terminal. This is true for both male and female connectors. The male housing has female pins and the female housing has male pins. Some companies reference the housing gender while others reference the pin gender.
Tamiya connectors are useful because the locking mechanism ensures they do not come undone easily, and they are therefore reliable for use in remote-controlled aircraft, cars and the like.
The connector physically isolates the positive and negative wires so that the connectors remain safe to use in damp conditions. This makes them safe for use in relatively high-current applications in dirty conditions for example, model boats or RC cars used outdoors).