Most new vacuum belts will be drastically different in size (usually smaller and wider) than the used belts. This is due to the fact that belts stretch and wear as they are used. Most new belts usually require the belt to be pulled and stretched into place.  
 

(2pk) Hoover 59139-191, 38528-032 and 40201147 Belt Fits Twist & Vac, Sidewinder