MRP ARg Chainguide – Braze-On Mount 38-54t Braze-on Black. Whether its the weekly group ride or the A race of your season dont let a dropped chain leave you panicked greasy and desperately chasing. The new ARg chainguide offers 25 grams of vital insurance for every 1x all-road or gravel bike. With its compact design the ARg is so lightweight and quiet that youll barely even notice its there.