Use on doors requiring privacy, can be locked inside with a turn button and unlocked outside with provided release tool. Recommended for bedrooms and bathrooms. Do it yourself, installs in minutes with just a screwdriver, all the hardware you need is included for a hassle-free installation, detailed directions provided. FITS STANDARD DOORS: Fits standard size doors 1-3/8" to 1-3/4" thick, adjustable latch backset from 2-3/8" to 2-3/4" with just a twist during installation. BOX INCLUDES: Exterior and Interior Knobs, Screws, Adjustable Latch, Strike Plate, Emergency Unlock Tool, Installation Hardware, Install Guide.