FAQ Knowledge Articles

Marvin Windows and Doors is discontinuing the use of EZE Spiral Balance Tubes in Clad Ultimate Double Hung - Next Generation (CUDH-NG), Clad Ultimate Double Hung Round Top – Next Generation (CUDHRT-NG) and Clad Ultimate Double Hung – Next Generation IZ3 (CUDH-NG IZ3) operating windows. The EZE Spiral Balance Tubes are replaced with either a Block and Tackle Balance Tube or a UL Hybrid Spiral Balance Tube. The weight of the sash will determine which balance tube will be selected. The change was implemented starting with windows ordered on April 25, 2016.




Sash Weight

Balance Tube Type


up to 35 lbs

Block and Tackle

> 35 lbs

UL Hybrid Spiral


up to 30.6 lbs

Block and Tackle

> 30.6 lbs

UL Hybrid Spiral