Tactical Skull Star Spare Tire Cover Dust-Proof Wheel Tire Cover Protector for Jeep SUV RV Trailer Car. Material: Polyester Size: 14 Inch, 15 Inch, 16 Inch, 17 Inch Package: 1 X Spare Tire Cover Cover Size Guide: Tire sizes are listed in the detailed description, please measure before purchasing. Cover Size 14" fits for tire diameter 60-69cm/23-27inch. Cover Size 15" fits for tire diameter 70-75cm/27-29inch. Cover Size 16" fits for tire diameter 76-79cm/29-31inch. Cover Size 17" fits for tire diameter 80-83cm/31-33inch. Spare Tire Cover Diameter Calculation Guide: Step 1: Find your tire parameter. It is written on your tire side. Step 2: Calculate your tire diameter. If your tire is written with P225/65R17, A=225 B=65 C=17. Tire Diameter=A*B/500+C*2.54 =225*65/500+17*2.54 =72.43cm. According to the sizing guide, 15" spare tire cover is the size that fits your spare tire. Product performance: The silver-coated sunshade fabric can prevent dust and water splashing, and also prevent sun and corrosion, to keep the spare tire clean. Applicable scenario: The universal model is applicable to Jeeps, trailers, SUVs, trucks and many vehicles. Accessory structure: With nylon rope and buckle, it can be adjusted in size, easy to install and disassemble, without tools. Washing instructions: It is recommended to wipe and clean with wet cloth.