C27MMX is a 2mm top deck. It provides greater forward traction as it assists in keeping the chassis flatter front to rear especially under acceleration. the open front section will provide less initial turn in steering whilst providing more mid corner steering. the rear section of the top deck with the added bracing provides increased rear end stability through corners. 

the full length top deck is a great tuning aid for large sweeping tracks that require stability entering, through and exiting corners. it is advisable you have a full length deck in your pit bag.