CTP Primary Air Filter Part Number 6I2503 CTPSecondaryAirFilterPartNumber6I2504 *** Other part no. not included in the list are available. The open and closed caps end caps are fabricated using a polyurethane material that is highly elastic and provides a high resistance to vibration and impact. The perfect union of the end caps with the filter paper element makes for uniform seal that does not permit any bypass of incoming air between these surfaces. The end caps are adhered to the filter element chemically with a soft elastic material providing the benefit of a perfect seal and assuring the flow of air thru the filter medium. IF YOU CAN'T FIND WHAT YOU ARE LOOKING FOR, PLEASE CONTACT US. PRICE AND PART NUMBERS ARE USED FOR REFERENCE PURPOSES ONLY.