I am looking for a cheap replacement for the missing rubber eyecup on my Pentax UCF WP compact binoculars. My sons lost one of the round rings that cushion your eye as you look through. I can't see them online except for around $30 direct from Pentax. I was thinking of replacing both of them with some type of foam padding or a small piece of soft rubber hose. anyone have ideas of what could be used? The missing part just adds a little cushioning to the round end of the eyepiece tube. Thank you, Kimberly