The P/N 300-605 & 300-605BK Ultra Lo-Ram plenum tops are designed as part of the Holley LS Ultra Lo-Ram EFI intake manifold kits. The Ultra Lo-Ram kits are intended for boosted engine applications where the requirement of a intake manifold plenum burst panel may be recommended to protect the engine from intake plenum back-fire. The 300-605 plenum top is machined for a standard "large" 6-1/8" x 3-1/8" burst panel. SFI approved burst panels, burst panel frame sets, and gaskets may be purchased from various manufacturers such as Allstar Performance or Specialty Fasteners.P/N 300-605 has an as-cast satin finish and P/N 300-605BK has a powder-coat black finish. Flange seal o-ring cord and the mounting fasteners are included in the kit.