🎶 Elevate Your Listening Experience! Designed specifically for Etymotic Research ER4 and HF series earphones. Includes a handy changing tool for effortless filter swaps. Keep your earphones performing at their best with these replacement filters. Ensure your audio experience is always top-notch with these essential replacements. Weighing only 0.008 kg, these filters won't weigh you down. Fits ER4/HF series 4 filters + tool 0.008 kg lightweight The Etymotic Research ER38-46 Green Filters and Changing Tool is a must-have for audiophiles, providing 4 replacement filters and a convenient tool to maintain your ER4 and HF series earphones, all while being incredibly lightweight.