187877
It was available in the M39 lens mount , or " Leica thread mount " , a bayonet mount to fit early Zeiss Contax cameras .
 Leica, Zeiss
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Leica, Zeiss