The R5408 is a resistance decade box used for prototyping and testing circuits, offering 7 switch-selectable decade ranges spanning roughly 1 ohm up to about 11.1 megohms in 1-ohm steps. Slide switches let you dial in a target resistance quickly, and three binding posts allow isolated substitutions, with rated substitution accuracy of about 1%. It's built for bench work in the 32-122F operating range and is a compact, durable tool for circuit design and troubleshooting.