LIFTMASTER model 355LM receiver. It receives using rolling code (changes each time) on frequency 315 MHz, Security plus (315 MHz).
The warranty on the 355LM garage door receiver is 1 year from LIFTMASTER.
The model 355LM is discontinued.
LIFTMASTER model 355LM receiver instructions and owners manual in PDF format at NO CHARGE!
liftmaster_355lm_om.pdf (0.16 MB in English) This requires Acrobat 10 or higher