Factory Road Disc Wheels are factory built to meet the needs of todays disc brake bikes. Disc brake road bike wheels are designed to fit disc road bikes, usually with 142 x 12 / 100 x 12 hubs for modern bikes, but be sure to check before ordering. Gravel bike wheels can be 27.5 / 650b or 700c. Gravel wheel rims tend to be built tougher to cope with the extra demands which varied  terain can  throw at them. Tubeless compatiblity means they can run tubes (clinchers) or tubeless, also check whether wheels are centrelock or 6 bolt if you want to use your existing disc rotors.