YOU ARE BUYING SOFT BELLY BANDS MADE OF FLEECE MATERIAL. NO INSERTS NEEDS. JUST MEASURE YOUR DOG AROUND HIS WAIST AT HIS PEE PEE AND THATS THE MEASUREMENT YOU ORDER. I WILL ADD 3-4 INCHES FOR THE VELCRO OVERLAP. WHEN WASHING CLOSE VELCRO AND THROW IN WASHER AND DRYER.  LET ME KNOW IF I CAN HELP. THANKS FOR LOOKING