What's This?

[Trikebent]

This is in the boost pressure line. 1st gen Banks turbo. Is it a check valve?

 

[sjwelds]

Looks to me like just a splice in the line.

 

[cozinsky]

It's just a push connect union. Those are commonly used on air lines in big trucks. Someone must have cut or damaged the line at some point and patched it back together.