Amazon.com: Etymotic Research Tuning Kit for ER Series Earphone with 5 Different Filters (ER-DAMPER5PACK) : Electronics
ISPRING High Capacity 20 in. x 2.5 in. Water Filter Replacement Cartridges Fine Sediment Filter - 5 Micron (25-Pack) FP25X25 - The Home Depot
Musician Earplug Filter (single)
Assembled in USA OCS CS52 Compatible Refrigerator Filter by Instapure. Instapure REF-IPBQ-1 ULTRA filter fits 3M 55866-06, CS-51, CS-522 & more. As low as $19.95 – Instapure