Our polyester “L” seals are closed on one short and one long side at a 90-degree angle. They are offered in a variety of sizes. Made of inert, acid-free polyester, sleeves are a popular choice for preservation of photos, negatives, letters, documents, drawings, and many other flat items. “L”-seals are particularly good for delicate or brittle items as the enclosure opens easily, allowing gentle insertion of the artifact. The size listed is the size which will fit inside the envelopes; they are slightly larger externally. Packages of 10.