Plantronics Versa Tips - 25640-01 - $2.95 each
Works with your H31CD headset. The soft, pliable Versatip eartip gently conforms to the natural contours of your ear while providing the acoustic seal necessary to block out background noise. The Versatip is a great accessory for an already ultra-lightweight headset. One-size-fits-all. You should clean eartips daily and replace them every six months or sooner.