This is the in-line vacuum line filter for the HKS SSQV BOV.  It is also very useful for other BOVs, vacuum manifolds, boost controllers, MAP sensors, wastegates and vacuum line filtration needs.

Comes as pictured, the housing is clear so that you can see how contaminated the filter becomes and change when necessary.  Protect your expensive BOV, boost controller, wastegate and other vacuum/boost related items!