The RØDE Pin-Cap is a replacement low noise Omni Capsule for the PinMic™ microphone.
The NT45-C is an interchangeable cardioid capsule for the NT4, NT5, NT55 or NT6 microphones.
The NT45-O is an interchangeable omni capsule for the NT5, NT55 or NT6 microphones. As the omni polar pattern is designed for equal sensitivity on all sides, use it when you want to pick up a more overall 'room' sound.