This set allows complete removal of the EGR pipe (exhaust to intake manifold). The EGR Block Off Cap blocks the exhaust side of the EGR pipe, after fully removing it. The corresponding blanking cap blocks off the intake side.
It CNC machined stainless steel cap with special design to block (cone vs. cone) the EGR pipe.
Please do not confuse this purpose machined product, with cheap dome nuts sold for the same purpose.