A spinal interbody device is provided having a cage and an anchor. The cage includes a center portion with a first surface and a second surface. A first arm and a second arm extend from the center portion with the first arm having a pair of first projections and the second arm having a pair of second projections. The pair of first projections and the pair of second projections are disposed on opposing sides of an open side. The anchor includes a blade that is movable between a first position and a second position. The blade is disposed to engage the first surface and deflect as the anchor is moved from the first position to the second position. Wherein the blade is at least partially disposed between one of the pair of first projections and the center portion when the anchor is in the second position.