The Godox SA-03 150mm Lens Optic has been designed specifically for use with the Godox SA-P projection attachment. This lens enables you to get a smaller projection than the 85mm optic that comes included with the SA-P projector. It also enables you to make projections over larger distances. The Godox SA-03 150mm Lens Optic for the SA-P projector, is perfect for people, who are wanting to get a smaller projection or want to make projections over longer distances than what they can achieve with the 85mm optic that comes with the SA-P Projector.