Aeroflow 1-1/2" Billet Aluminium Weld-On Filler with Purple Cap (AF460-24PUR)1. 5" ALUM WELD BUNG AND CAP Part Number: AF460 24PUR Billet Alloy Weld On Filler & Cap. Aeroflow Performance non vented filler caps are manufactured from 6061 T6 aluminium and are supplied with BUNA N (wide range of fuel and oils) and EPR (Nitro methane fuel O Ring seals. Available in 1", 1 1 2", 2", 2 1 2" & 3" diameters in Blue, Red, Black,Gold, Purple, Raw, Polished and Silver anodized finishes. Bore Size: 38. 1mm (1 1 2") Neck O. D.: 46mm (1 13