L2 Aviation issues supplemental type certificate (STC) which are a type certificate (TC) issued when an applicant has received FAA approval to modify an aeronautical product from its original design. The STC, which incorporates by reference the related TC, approves not only the modification but also how that modification affects the original design.
"It was a pleasure working with L2 and its employees. The trays and kits we ordered from L2 were very well constructed and packaged. I wish all of our vendors put as much pride and workmanship into their products and were pleasant to deal with. "