Brass Knock Fitting with Bolt - Indmar Engine HardwareRestore a secure, leak resistant connection on your Indmar engine with this brass knock fitting with bolt. Designed as a compact threaded adapter plug style assembly, it combines a durable brass hex fitting with a steel hex head bolt to help you service or replace worn, corroded, or damaged engine hardware. The brass body offers excellent corrosion resistance, while the bolt provides a strong, reliable hold for marine and engine bay environments.