CertainTeed Vinyl Carpentry™ Functional Trim offers a complete line of J-channels, starter strips, utility trim, etc. All the items that are necessary components of every professional siding installation. CertainTeed accessories are precision color-matched to the siding on your house, and are all covered under the same siding warranty to assure you that your entire siding job is backed by the best. We make sure you don't have to sweat the small stuff, by providing the finishing touches that make your exterior design system complete.