Astro-Physics 16mm Back Focus Spacer Extension for QUADTCC with 3.27" Thread

You will need to add the proper length back focus spacer extension when purchasing the QUADTCC in order to achieve the required 80.8mm spacing. Please reference the chart below.  Telescope Part # Length of Extension Spacing w/ 3.27" Extension Spacing w/o Extension AP 130 GTX EXT327-22.1 22.1 mm 80.8 mm 102.9 mm TEC 140 EXT327-18.3 18.3 mm 80.8 mm 99.1 mm TEC 160 EXT327-17.0 17.0 mm 80.8 mm 97.8 mm TEC 180 EXT327-16.0 16.0 mm 80.8 mm 96.8 mm ???? EXT327-34.1 (new in May 2021) 34.1 mm 80.8 mm 114.9 mm If you have a TEC telescope, you will also need to order a Drawtube Endcap (S35RFAA) for the focuser. This only applies to the TEC focusers and is integral to the Astro-Physics 3.5" focusers, but is not needed as a separate purchase. The S35RFAA screws directly onto the drawtube's 4.1" x 24 thread (same as Starlight Instrument's 3.5" focuser endcap thread). If you own more than one telescope that can use the QUADTCC, just substitute the required back focus spacer extension