CHAMBERLAIN model HD420EV residential opener is a 1/2hp chain drive. It is part of the value. This garage door opener has an ac motor on 110vac. A battery backup is not available. The remotes are rolling code on MyQ. The rail is style is Split Square.
The warranty on the garage door opener is Lifetime on the motor and 5 years on the remaining opener parts from CHAMBERLAIN.
The model HD420EV is still available.
CHAMBERLAIN model HD420EV residential opener owners manual and instructions in PDF format at NO CHARGE!
VIEW / DOWNLOAD by clicking HERE
(4.68 MB in English) This requires Acrobat 10 or higher