Compatible Models: 3508,2112, 21129, 2690, 1520, 23T7, 23T7V, 3130,31033 Fit many models including the 3508 series, 2112, 1520 series, 2690, 23T7 series, 3130 series and 3120 series Recommended to replace the belt every 3 to 6 months to maintain the cleaning performance of the machine Package Include two belts;Replace Parts:1604895 160-4895 2037034 Easy to install, durable, cushioning effect, low noise, anti-skid wear