Function And ApplicationKeyless,but latch with locking mechanism. This door knob typically found on bedroom or bathroom doors where privacy is needed Easy InstallThis privacy door knobs are easy to install. All hardware, install instructions and template included Emergency Release FunctionThere is a emergency release hole on the exterior rosette, when emergency happened, the door can be unlocked from the outside by pushing a hex key(included,come with the product) through the emergency release hole Important Product ParametersAdjustable Latch Included. Fits any 2-3/8" or 2-3/4" backset. Fits all doors 1-3/8" to 1-3/4" thick ServiceIf you encounter any problems, please contact us and we will reply to you within 24 hours