Good evening、It's a spacer, but is the shape of the tube O type different from that of the U type? I only have a U type and have never seen it (laughs) Old(Maybe 10 years with serial number)SNZF spacer is also black、The spacer of the movement removed from SKX is also black、When I put it in, I notice that the lid does not close and the thickness is different。 gray(thin) black(thick)I thought, but am I making a mistake? NH36 spacer and SNZF spacer are similar at about 3mm? What is the color of the spacer changed????Beginners don't understand why, so can anyone please tell me?。 Is it okay to put a gray spacer?、2Do you separate them and replace them?(Sweat thank you。