Baader Planetarium VariLock 29 T2 Extension Tube 20-29mm with Graduated Length Scale

I learned a few things about the Baader components when I recently purchased a pair of Hyperion eyepieces. The first thing is that there is an additional adapter needed to mate a "T" tube (and thus this extension tube) to the eyepiece. I mention this because it's relevant to how you may use this particular bit of equipment.Secondly, my unit arrived in a box. No instructions. It took some head scratching to figure out how to assemble and use the components... one of those components seems to have nothing to do with the others and fits in no manner with the rest of the system. Lacking instructions certainly doesn't help.What would you do with this?You can adjust the tube length and lock it. Theoretically you can fine tune either the focus (when used on the eye-side of the eyepiece), or the focus/magnification when used on the telescope side of the eye-piece. In each case you'll need an adapter to attach the T-2 to the eyepiece. Presumably you're most likely to use this device on the "eye" side" of the eyepiece. You might even use it stand-alone without an eyepiece.Other alternatives are to use fixed size T-2 extension rings. Until you tighten the lock nut, the whole apparatus is pretty wobbly. Unfortunately to actually do the fine tuning is painful since you must be able to completely rotate the imaging device WITHOUT unscrewing it. All in all it's a "meh". Perhaps it's a bit more useful than having multiple fixed size extension rings, and perhaps slightly more accurate IF you're willing to jiggle with it.