You could make it out of brake tube also. Since the oil filter is mounted to the engine, it vibrates with the engine. The flex is redundant. I bent hard lines for my bypass filter. Any real auto parts house should have all the brass fittings to convert it to a hard pipe. The filter itself uses an 1/8 inch pipe thread for the elbows. You can get different elbows to work with the flare of the brake tube. You can also get by with a farell type fitting so you don't have to flare it.
