BEST FITNESS BFVK10 Vertical Knee Raise. The BFVK10 Vertical Knee Raise stands ready to help you tighten your abs and define your upper body muscles. This single-station, multifunction workhorse is intelligently designed to combine ab-blasting vertical knee raise and oblique routines with muscle defining dip, pushup and chin stations. Built to last and designed to perform, the BFVK10 offers a lightweight solution to a heavyweight series of upper body exercises.