knock door sound - Knock Knock! Who does that sound like? This application can help you to replace knocking on the door, easy to use, repeat the sound, & stop every time. Features * 10 kinds of knock sound * knock, bell, metal door knocker * repeat & stop sound * Modern flat design * colorful design * Full-screen app * Optimized for all smartphones and tablets contact us website : luciandev.blogspot.com instagram : @luciandev_ email : [email protected]