A projector's throw ratio is defined as the distance (D), measured from lens to screen, that a projector is placed from the screen, divided by the width (W) of the image that it will project (D/W). The ratio, like any ratio, is dimensionless.
BenQ   - LS1LT3  Long Zoom 2 Optional Lens - Lens - Jamsticks
BenQ  - LS1LT1 Semi Long Lens - Lens - Jamsticks
BenQ  - LS1ST1 Wide Zoom Lens - Lens - Jamsticks
BenQ  - LS1ST2 Ultra Wide Lens - Lens - Jamsticks
BenQ  - LS2LT2 Long Zoom 1 Lens - Lens - Jamsticks
BenQ  - LS2ST3 Wide Fix Lens - Lens - Jamsticks
BenQ - LS1SD Standard Lens - Lens - Jamsticks