How it's made. PETG throughout - oil does not touch it, and it never softens on a warm valve cover. A 110 mm bowl into a nozzle with a coarse sawtooth external thread cut to the size you choose: Toyota and Lexus M37 x 3.0 (the size their filler necks share), or the major diameter and pitch you measure on your own cap with a ruler. 45-degree thread flanks and a 2.4 mm wall, so it prints standing on its mouth with no supports. The cap threads onto the nozzle so nothing gets into it between changes. The make and your own word stand 1 mm proud on the bowl. Never printed in a filled or glitter filament.