Used with the Octopus III for alignment of servos (cannot be used with the Octopus II). Just one of these needed for all of your Octopus IIIs. Comes with a 7′ cable which allows you to stand next to your turnout while aligning the servo – no more acrobatics and hanging upside down below the layout! The cable is a 6-pin straight data cable (not a phone type cable). Board is 2.7″ x 1.7″ in size.