LIFTMASTER model 423LM receiver. It receives using on frequency 390 MHz.

The warranty on the 423LM garage door receiver is 1 year from LIFTMASTER.

The model is still available.

LIFTMASTER model 423LM receiver instructions and owners manual in PDF format at NO CHARGE!
VIEW / DOWNLOAD by clicking HERE
liftmaster_423lm_om.pdf

(0.13 MB in English) This requires Acrobat 10 or higher