Search for: BOA SI Belt Provides support for the Sacro-iliac joint. Excellent adjunct to post-injection pain following an S.I. procedure. Reduces pain and swelling for strained or lax Sacro-iliac ligaments. Part # Waist Size Size 510243 (25" - 35") Small 510244 (35" - 45") Medium 510245 (45" - 55") Large