Summary: Personal Experience It turns out there are various subtypes: P1273, P1273n, P1273B, P1273i. This review is for the P1273 only. - The P1273 plain version does not have any filters, nor a regular USB port. - Easy to set up and use. - I like the automatic keystone correction feature. - The horizontal and vertical controls on the menu are only for centering the laptop projection in the screen (by millimeters).