Metal ROOFING SCREWS: (250) Screws x 2-1/2" BROWN Hex Washer Head Sheet Metal Self starting/self tapping ~ EPDM washer. Colored for corrugated roofing EASY INSTALLATION and USE: Install and connect at the air vent or at other places in the car easily. Just put the phone on charger and then charging begin, If the magnetic force is not strong due to thick phone case, please stick the metal ring which included in the package USE METAL RING! For solid placement you need to attach metal ring to the phone case. This is because most phones are not made of metal. Magnets in the charger pad cannot stick to phone cases made of materials other than metal. NOTE: We recommend to use USB car charger adapter with output 2A, thus avoiding working problems due to the unstable current from the built-in USB ports of the vehicle COMPATIBILITY: Qi standard wireless car charger(5V-1A) for Qi enabled devices like iPhone X/8/8 Plus Samsung Galaxy S8 S8 plus/S6/S7 Galaxy S6/S7 Edge Note 5, Google Nexus 4/5/6/7, LG G3, Motorola Droid 5, HTC Droid DNA/8X, Nokia Lumia 920/930/820/1020/1520/icon929/822, and devices that require their own separate wireless charging adapter Ytech Wireless Charging Receiver such as the Galaxy S5/S4/S3/J7/Note 4/3/2, iPhone 7/ 7 Plus/ 6/ 6S/ 6 Plus/ 6SPlus,/ 5/ 5s/ 5c/SE 2-in-1 MAGNETIC WIRELESS CAR CHARGER: Combined with phone charger and holder,no more tangled cords or cables in car anymore. Charging while navigating has never been simpler