Low gearing is rare on Scott trailbikes, but they got it right this time. The red aluminum guard bolted onto the ISCG tabs keeps the chain from destroying the carbon frame. The covered port is for the internal routing of a dropper post. If a Reverb Stealth Dropper post is used the housing re-enters at the back of the seat tube. (a dropper post is rudely missing on this otherwise wonderful trailbike)