An optional part of the modular Astro T-2 system, the Alpine Astronomical Baader Sliding T-2 Focuser is ideal for use with 1.25" eyepieces and off-axis guiders and provides up to 10mm of additional focus travel with locking thumbscrews to set the perfect focus position. It is placed between eyepieces, diagonals, bino-viewers, or other accessories and the telescope focuser drawtube or visual back to provide additional focusing room for sharper images. As with all of the Astro T-2 family of accessories, the focuser has male T-2 threads on one side and female T-2 threads and an eyepiece insertion sleeve on the other for complete compatibility.