Sleeve nut connector for metric type male unions. Fitted to cars Pre Servo before 1988, to allow engine subframe assembly to be installed on the assembly line, and then connected to PDWA valve as brake lines already fitted on shell. When the servo was fitted in 1988 they used a pipe from the PDWA valve on bulk head with a large female end to join the pipes but we suggest you replace with a single pipe 13" [link]HMV013[/link} or 15" HMV015 long.