I have an old pair of Zeiss FL 8x32, bought second hand a few years ago. The eye cup on one barrel wouldn't extend, without unscrewing the whole eye cup mechanism. I threw the problem over to Zeiss' centre in Cambridge, and (after one 'reminder' email) received two new eyecups in the post yesterday - no fuss, no bother. Screwed in inside two minutes, and up and running again. Good going, chaps! Alpha response!