138-173mm ID Orion PinPoint Telescope Focusing Mask

• 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 138mm to 173mm (5.43″ to 6.81″)
• 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

item #40008