Spreader Bar

Hardware required: 
2 x (M5 x 20 bolt + nut)
2 x (≤ 28 mm wide nylon straps + buckles)

Circumferences:
S = 41 cm
M = 50 cm
L = 60 cm

Given that the cuff only covers ~⅓ of the thigh you don't need a precise fitting whatsoever.
Gap for nylon strap is only 4 mm wide, may require some thought and strength to pull strap through.

Spreader Bar Print Settings:

DISABLE SKIRT LOOPS FOR SPREADER BAR

Ensure wall thickness is 1.6 mm for spreader bar. Stick around for first layers on spreader bar as the bottom layer perimeter fill pattern is delicate, precise, and infuriating.

Cuff Print Settings:

NO SUPPORTS NEEDED!

In built supports supplied, snap off when finished. Trust in the overhangs!
Strength of cuffs is much less important, ≥ 1.2 mm walls preferred, 2.0 mm walls optimal.

Nyashi's Shorter and Longer Spreader Bars