Metal.

Unless damaged or cracked generally you never need to change it, too easy to flush that out there......... .....I've never changed an entire fuel line on a car in 40+ years of working on them unless going to bigger say for race car.

You can patch small sections in rubber and i commonly end up with last 3 foot or so rubber (from fuel pump up) on these since different things make me cut line shorter and shorter for things. I NEVER use that small OEM screw-in-carb filter, it's just asking for constant trouble in today's world of ethanol laced fuel. I always use a much bigger inline filter maybe 6 inches out from carb.

Line is either 5/16 or 3/8, thinking the smaller. FYI, steel brake line can be used in place of the metal part and easy to get, bend, and patch pieces together, cheap as well. Run line in factory location and be sure to fasten it down SECURELY even if you need to make up a couple more clamps than original, say if you had to patch in a short rubber piece in the middle of the run.

There you go............ ..