The line guides and spools, parts that undergo perpetual line friction, are coated with titanium to make a smooth, abrasion-resistant surface.
(parts; undergo; perpetual line friction) (The line guides and spools; are coated; with titanium; to make a smooth, abrasion-resistant surface)
parts The line guides and spools
undergo are coated
perpetual line friction
with titanium to make a smooth, abrasion-resistant surface