Upgraded 4 rounds of passwords are more secure. The 3 rounds of passwords are improved to 4 rounds of passwords, which are stronger and more secure.This better protects older and more naughty children. Don't worry - you can apply these locks any where you need to, and move them if necessary. Installing Easily: Use High quality Adhesives that have been tested for strong hold but will not leave residue if taken off (Takes a lot of force to take off) Refrigerator lock will instantly stick to fridge, not require drilling or screws.The lock is small and compact. So it does not look so big on your refrigerator. No more fear accidentally harming your child with the device built to protect them. It can adapt to almost any surface.So child safety locks can even be fitted onto your drawer,seat,refrigerator,window,cupboard, oven,freezer. Instructions: Please clean and dry the surface of Refrigerator. Pre-assmble the upper lock arm to the base. Find out the suitable palce and mark the location. Colour:Black / White Material:PPA+ stainless steel Package Contents: 1 x password lock Only the above package content, other products are not included. Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.