This sale is for a Seiko 1970s Automatic Chronograph Watch Crystal. 

Original Sternkreuz XMD 330.821 glass crystal , made in Germany and not a cheap acrylic crystal . To replace Seiko 330W18GNm .

 to suit the following models 

6138-8080 , 6139-6000 , 6139-6001 , 6139-6002 , 6139-6005, 

6139-6007 , 6139-6009 , 6139-6010 , 6139-6011 , 6139-6012

6139-6013 , 6139-6015 , 6139-6017 , 6139-6019 , 6139-6030 

 6139-6032 , 6139-6040 , 6139-6041 , 6139-6089