How to measure yourself for a great fit:

Measuring for the belt:

Use a measuring tape (like the kind for sewing) and wrap it around your hips where you would wear a belt. Use the number of inches where the tape measure completes and crosses over itself. You should add a few (3-4) inches to this measurement for size fluctuation and room for sizing adjustment. If your measurement fits within size A, we recommend you purchase size A to avoid extra waist strap length that could flop around and annoy you.

Measuring for Leg Straps:

Wrap a belt around your waist where you would normally wear one (this is where your harness should also go). Take the tape measure and put one end of it against the belt front and center (pretty much right under your belly button). Then pass the tape measure between your legs, around one of your legs and back to where it started in front of you. It should be tight but not uncomfortable. Subtract 15 inches from the number of inches you get where the tape measure meets itself.