100109799 AO Smith Promax 4Year Stage I Stretch Warranty (Kit Contains Instructions Extension Sticker Hot Water Outlet Secondary Anode Assembly And Cold Water Nipple Heat Traps) Old# 9004329105 Applicable To The Following Electric Heaters: Ent-30 Ens-30 Ent-40 Ens-40 Ent-50 Ens-50 Ent-55 Enl-50 Enlb-50 Enl-36 Enl-30 Enlb-30 Enlb-40 Ensb-30 Also Applicable To The Following Gas Models: Gcb-30 Gcb-40 Gcrh-40 Gcrt-50