Malco FDS1 Flexible Duct Support Eliminates air flow restrictions from kinks and sag Increases efficiency, reduces utility bills, improves room comfort Accommodates 4 -16 inch diameter, insulated or un-insulated duct Uses 36 and 48 inch nylon cable/zip ties (Malco TY34 and TY48) Strong, lightweight 100% recycled polymer construction will not weigh down ducting