Cokin BP400A P-Type Standard Filter Holder
The Cokin BP400A is Cokin's standard P-Type filter holder, and as such, the backbone of the Cokin P-Type creative filter system. The Cokin BP400A P-Type Holder attaches to your P-Type adapter ring, and can hold up to three P-Type filters at any one time.
If working with wide angle lenses, it is possible you may experience vignetting with the Cokin BP400A. Fortunately, Cokin do also make a wide angle filter holder, which only holds one filter at a time, but practically eliminates vignetting.