VINTAGE '75 ALPHA INDUSTRIES USAF N-3B JKT-SIZE GUIDE
How to measure
With arm relaxed at your side, measure from center back neck, to point of shoulder, and along the arm to the wrist (just below round bone).
Measure around body with tape leveled on the fullest part of your chest.
Measure around your waist with the tape leveled at the narrowest point of your torso.
Stand with heels 2 to 3” apart. Keep the tape leveled and measure around the fullest part of your hips.