surface texture in the first handle 34 and or the second handle 16 the adjuster knob 14 may allow the user 12 to adjust a bending force of the exercise device 10 in addition the adjuster knob 14 may provide the exercise device 10 with an additional gripping surface the adjuster knob 14 may be made of the same material as the first handle 34 the adjuster knob 14 may include notches 15 for easy operation the adjuster knob 14 may have a machined or molded surface texture for easy operation a window 24 may be located on the second handle 16 the window 24 may be made of transparent material the window 24 may be made of transparent acrylic transparent rigid plastic or glass the window 24 may allow the user 12 to check the setting of the resistance force the first handle 34 may include an end cap 20 to cover the open end of the first handle the end cap 34 may be vented the end cap 20 may be made of the same material of the first handle 34 the second handle 16 may enclose an indicator sleeve 18 and an adjusting force system 22 26 28 30 32 36 the indicator sleeve 18 may provide the bearing surface for the compression of outer spring 42 the indicator sleeve 18 may provide the bearing surface for the threaded adjuster 22 to turn in the indicator sleeve 18 may provide the bearing surface to react the tensile load on inner spring 38 the indicator sleeve 18 may be made of the same materials of the first handle 34 the indicator sleeve 18 may comprise two identical halves mated together a threaded.