A 37-degree flare filter insert in AN12, sized for the larger circuits where an AN10 screen would become a restriction. Dry sump scavenge lines, big-capacity oil circuits and high-volume fuel feeds all run AN12, and all of them benefit from catching debris before it reaches a pump or an oil cooler core. The insert fits within the AN joint itself, so it adds screening without lengthening the hose run or requiring a housing and bracket. It is a favourite on race engines where a spun bearing can send metal through the entire oil system in seconds. Inspect it during routine servicing, since a partly blocked screen restricts flow with no outward symptom until it becomes serious.