Chainguide for the BrazeOn Standard
For Round or Oval Chainrings
Chainring Size 36-40 (42)th or 42-50th 
Messure your BrazeOn Mounting Slot Standard 24mm length allows 42th Chainring in the low Size / Open Upper Slot is 18mm length - for 42th you need the 42-50 Version.
Weight 21.8grams incl. all needed Screws