4" Coupler Bulk plate (P)
4" Coupler bulkplate fits inside 4" Coupler. 1/4" plywood.
For thick wall couplers, such as PML Quantum and Phenolic Couplers. (bulkhead OD 3.74")
See next and previous bulkhead made for Aerotech, Madcow and other 4" paper couplers.