the camelbak lobo comes with a 100 oz bladder and also has 3 storage compartments ( 2 zippered and one just a pouch ) that i think works perfect for OCR. the 100 oz is more than enough fluid you will need you any race and the storage areas give you a perfect place to store any energy treats or anything else you may want to carry for your trek. it has a minimal profile so it dosent feel to bulky when running and has nice solid padding on the back area to make it more comfortable for runs. i only have two complaints about this unit one is the shoulder straps could use a little more padding to soften the stress it puts on your shoulders when running with 100oz if fluid and second there is no cap for the mouth nozzle ( but one can be purchases seperatly from amazon.com or any other site ) and that is a critical must for me in the mud runs you want to try and keep that area as clean as you can. i know some people perfer osprey but i have yet to use there gear and can not speak for it but for the $80.00 price tag of the lobo i think its a great starter hydro pack
