Versatile: If you're like a lot of retrofitters, finding screw holes to mount your ballasts, controllers or relays can be a pain in the butt. After all that work, its the last thing you probably want to do! Helpful: These convenient Velcro squares measure approximately 6.5x8cm (2.5x3in) and have a sticky backing. Clean the surface you intend to use, and mount em anywhere! Helpful: It's definitely a good idea to make sure all surfaces are clean before applying the velcro to the desired location. You know... because glue doesn't stick to dirt so well. Two-Pack: Each kit comes with two "male" and two "female" pieces, just enough to mount two components under the hood.