Replace those tie wraps with these spring clamps that maintain continuous tightening on your coupler. Pliers spread these to 26mm or 1 inch and close to 3/4 inch.  Use these on couplers with a 5/8 inch ID.  Makes your material last longer and makes for a tight coupler to header/pipe contact.  We use this size on couplers that join pipe stinger and after muffler or extension that exists rear of transom in Scales.