In the spirit of everything getting bigger in the world of Ultra4 racing… we are very excited to release the Spidertrax 2¼” 57.2mm Thread Aluminium Fill Cap & Steel Bung Assembly. As the title gives away, this massive 2¼” 57.2mm opening lets you easily peak inside the axle housing, great for gear inspect and easy filling. CNC machined from billet 6061T6, the Spidertrax cap is both sexy and held to high tolerance. A stepped shoulder on the cap makes threading quick & easy, and the larger outer filler cap indents provide a comfortable grip. Assembly comes complete with aluminium cap, steel bung, and o-ring.