Dell EMC ML3 Tape Library

I want to know the different between  (Dell EMC ML3 Tape Library part number (210-AVOY and 210-BKZL ) .
ML3/ML3E Rack Rails ( 770-BCUO - 770BFBR ) .
Enterprise Order -EMEA Part number ( 800-1091) and Power Vault Order - United Kingdom ( 800-10491 ) .
Send to me data sheet  for Them