The medium UPG fly box has the best combination of performance and quality. See-through case for quick Identification, twice the fly capacity of other fly boxes, durable, lightweight & water resistant, hackle clearance for large dry flies. Features:4" x 6" x 1.5"Weather Proof with Zerust Corrosion Protection � No More Rusted HooksSee-Through LidsFlytrap� Foam SystemDouble Sided, Holds up to 508 flies total Model Number: 33011UPC: 052857330113