The Side by Side Vixen Style Plate from Losmandy is a long mounting plate which supports two saddle clamps - one mounted at each end.

Each saddle clamp or plate is designed to accept the Vixen or Losmandy dovetail plate standard and the two clamps are placed 9.25" apart, center to center. The side-by-side plate allows two optical systems to be mounted right next to one another, a task accomplished by rotating your equatorial mount's saddle 90°.