Automatic Garage Door Lock Made By Liftmaster 841Lm. Product Details Features: Automatic operation, performs in tandem with the opener, so it always locks and unlocks. Anywhere assurance, smartphone monitoring with the myq app means homeowners always know that the garage is securesafety and security: Absolute protection, the automatic deadbolt lock makes the garage door virtually impenetrable audible security, the sound of the lock engages providing homeowners with assurance that the door is closed and secure. Compatibility: Works with three new select lift master auto lock capable garage door openers 8550w dc battery backup belt drive wi fi 8587w hp ac chain drive wi fi 8360w dc battery backup capable chain drive wi fi. The 841LM works automatically with your garage door opener so it always locks and unlocks with every operation of the door. The model 841LM 12V lock is only compatible with the following garage door opener model numbers: 8550WL, 8587WL, 8360WL, 8500W. It is not interchangeable with the 24V lock used on residential jackshaft garage door opener models 3800, 3900 and 8500. Add a lock to each side of the door for the best defense against high winds and storms and intruders Payment We accept PayPal and credit cards via PayPal. Taxes - US We collect sales tax, as required by law. Shipping We make every effort of shipping within 3 business day of payment clearing. The estimated delivery time is 2 - 5 business days from the shipping date. Policies If you do need to return your item, please contact us via email (you will receive an email when your product ships with additional details - Subject: Important information about your purchase). You will then be provided with a return shipping label and packing slip. Pack the item carefully. Include the packing slip, apply the shipping label, and return the item within 30 business days of the date you request a return, or your return will be canceled. Once we receive your order we will inspect the return. Please allow up to 5 business days of receiving the returned item for your refund.