William Optics FLT 156mm f/7.8 - WO Rack and Pinion 3.7-Inch - Red

The William Optics FluoroStar 156 imaging/visual APO Series

FLT 156 mm (6.14-Inch) Aperture f/7.8 Triplet Telescope OTA with a William Optics 3.7-Inch Rack and Pinion Focuser attached.

It's f/7.8 (at f/5.5 with an APO X0.7 flattener) triplet air spaces (FPL53 Design).