To all you 29er's out there!

what's the chain cover?

Hebie.

"...A chain case is a great idea for utility bikes – it weatherproofs your chain and keeps oil off your trousers. The Hebie Chainglider is a clip-together plastic sleeve for singlespeed or hub gear chains. It rests on top of your chain rather than attaching to your frame, which adds a bit of friction but means you don't need tools to fit it. .."