118-153mm ID Orion PinPoint Telescope Focusing Mask (Bahtinov)

Also known as Bahtinov masks, Orion PinPoint Focusing Masks will help you achieve precise focus in seconds.
This PinPoint Mask fits telescope tubes with an outer diameter of 118-153mm (4.64″ to 6.02″).
Orion PinPoint Focusing Masks produce a distinct, intersecting 3-line pattern once accurate focus is achieved.
Three Orion-exclusive adjustable padded pegs provide a secure grip once installed on a telescope.
Compatible with any type of telescope, and especially useful for astrophotography setups.