When ordering a nonlinear optical crystal, crystal orientation (or crystal cut) and size have to be known. The orientation is solely determined by the nonlinear optical process. For example, for type I frequency-doubling of 1064nm, BBO is cut at q = 22.8^o and f = 0^o. Where:q is the polar angle between the optical axis and the propagation direction, f is the azimuthal angle between the projection of propagation direction onto the XY plane and the X axis. If you aren't sure about the crystal orientation and merely provide the nonlinear optical process of your application,Dream Lasers' salesmen and engineers will help you.