the AX21630-2 filter fits with Caterpillar, Cummins Engines; Compair, Consolidated, Gardner Denver, Ingersoll-Rand, Joy Compressors
the AX21630 filter fits with MANN & HUMMEL
the AX21629-S filter fits with IHC (INTERNATIONAL
the AX21626-2 filter fits with Euclid, Hough Equipment
the AX21626 filter fits with CUMMINS
the AX21621-S filter fits with GENERAL MOTORS CORP.