Knobs for Orion's SkyQuest XT-Series (6", 8", 10", 12",  and 16") 4-Vane Phillips Screw Secondary - 25mm Long.

Fits: Orion SkyQuest XT-series with factory 25 mm long Phillips secondary collimation screws. This configuration is not as common as the set-screw secondary.

Secondary Characteristics: 4-vane spider, a deeply recessed center screw, and factory Phillips collimation screws. The secondary plate holding the screws is about 20 mm (3/4") thick.

Knobs: Black plastic, 13 mm (1/2") diameter

Threads: Stainless steel

Notes: The factory collimation screw length, measured below the head, can be either 25 mm or 32 to 35 mm long. Order knobs with the correct screw length for your application.