Product Overview Transform the sound, style, and performance of your Ford Focus ST Mk4/Mk4.5 with the ZERONINE DESIGN GPF-Back Exhaust System - engineered in the UK to deliver precision-fit quality, reduced back-pressure, and an exhilarating exhaust note without unwanted cabin boom. Crafted from premium 304-grade stainless steel, this 3-inch (76mm) bore system has been designed specifically for hatchback models to optimise exhaust gas-flow and retain everyday refinement while providing an unmistakably dynamic tone - enhanced further when you switch into Sport or Track modes. Each system is precision TIG-welded and finished to perfection, featuring a brushed matte finish, embossed rear resonator, and signature 09D carbon fibre tailpipe trims - a true fusion of performance engineering and motorsport-inspired design.