Configure or restore a compatible modular microphone assembly with a cardioid condenser capsule supplied as a capsule-only component. The AT4051B-EL designation identifies the capsule configuration; it is not a complete standalone microphone package. This distinction matters when replacing a damaged capsule or selecting a pickup-pattern component for an existing compatible microphone body. A cardioid pattern emphasizes sound arriving from the front of the microphone while reducing pickup from the rear. That directional behavior suits close-miked speech, instrument recording, and installed audio positions where rearward room sound or adjacent sources need to be reduced. As a condenser capsule, it forms the sound-capturing element of the microphone assembly and requires the appropriate compatible electronics and physical interface to operate. Western Digital SSM1-MICROELITE-IJ corresponds to the AT4051B-EL cardioid condenser capsule-only configuration. Select it when the requirement is specifically for the capsule rather than a complete microphone, cable, power module, shock mount, or other accessory. Verify mechanical and electrical compatibility with the microphone assembly already in use before installation, particularly when replacing an existing capsule in a modular system. The supplied component is intended for focused capsule replacement or microphone configuration work where a cardioid response is required.