The Eheim Air Pump Replacement Felt Pads is a handy pack of spare parts for keeping your Air Pump working at its best. It is particularly intended for use with Eheim Air Pump models 100 (3701) 200 (3702) and 400 (3704). This pack contains four carbon air cleaner pads for use with the pump and two felt pads for use with the Eheim diffusor. At a glance: Designed for use with Eheim Air Pump models 100 (3701) 200 (3702) and 400 (3704) Contains four carbon air cleaner pads and two felt pads for use with Eheim diffusor