Prevents door slamming from the HVAC running. Significantly improves air circulation between rooms Air passes right through the vents keeping everything in better balance when doors are closed Easy to install, takes about 10 minutes. Screws are included Material: plastic; Many colors available to match your design. Fits together nicely HOW TO INSTALL: Measure and draw lines on the door, just drill 4 holes in corners and use a jigsaw to cut the 4 lines, pop in the vents and screw them together