This Selector is an Electrical Control Device Designed for Layouts of Any Scale by Atlas Model Railroad. FEATURES: SPDT. This device enables the operation and control of two trains at the same time. It has four single-pole, double-throw switches to provide two-cab operation for four blocks. May be ganged together in any number to control additional blocks without inter-switch wiring. Can be used as area selectors for four-cab operation. Couples with #220 Controller (ATLU0220)--not provided in package. Instructions are listed on the back of the package. INCLUDES: One Selector with Screws REQUIRES: Screwdriver COMMENTS: If your layout contains a reversing loop or wye, an Atlas controller must be added to the control panel. 5/4/95sk kr8/9/01 ir/jl