The Baader VariLock T-2 Extension Tube gives you complete adjustability to enable you to exactly set or vary the spacing between T-2 components. The Varilock is the perfect thing for adjusting your back-focus when introducing a focal reducer, field flattener or any other optical or imaging system components. Full internal threading and blackening kills any stray light reflections. 2" OD enables use in any 2" system.
The Baader VariLock extension tubes feature an accurately engraved graduated scale, shown in 0.5 mm gradations, for an easy visual determination of the tube length. Simply rotate the inner tube until the desired length is reached, then tighten the lockring with the included spanner wrench. The connection is very sturdy, and you'll be so happy with the length adjustability factor! The Varilock 46 variable extension tube can be set to as short as 29mm to as long as 46mm. If you need a shorter variable extension tube, take a look at the Baader Varilock 29 (T2-25Y), with a range of 20mm to 29mm.
The Varilock 46 is also perfectly suited for setting the correct spacing of the Baader RCC-I coma corrector onto DSLRs (when adjusted to 36.5mm). As an added bonus, if you wish to image through a DSLR, the external T-threaded portion can be removed and replaced with an included dovetail ring, allowing you to attach a t-ring matching your camera's mounting system.