Cant seem to attach photo. It's the climate control hose. At the upper end enters into firewall behind dash. At lower end transitions to steel tube which ends with a union down by oil filter.
I think this is the high pressure line from ac compressor to expansion valve under the dash.Mine had leak due to old age. Got a local ac shop to make up a new one for reasonable cost. Got remove instrument panel and battle with confined space to fit it.