Reddit mentions of Xlab Mezzo Cage Pod, Black

Rather than water bottles which generally have narrow necks, there are containers actually designed for holding things in the bottle cage that work much better and they're fairly cheap.

Consider using something like this for your spare tubes/multitool/co2 and any other items you carry.

http://www.amazon.com/gp/aw/d/B00DQFV2NK/ref=pd_aw_fbt_468_img_2?ie=UTF8&refRID=0VP5TQFD7KW227KVVJQJ

I keep everything behind the saddle. I use these items:
http://www.invisciddesign.com/R3.htm
http://brandscycle.com/product/xlab-x-strike-inflation-kit-209717-1.htm
http://www.veissgear.com/#!gallery/c1utd

My spare tubular tire is velcroed behind / between the 2 water bottles. All the CO2 / inflator is on the X-strike kit and the levers are on the CO2. I have a small multi-tool in the middle of the R3. Sometimes I feel it is a bit overkill and bulky but it works for me.

One of my friends uses one of these and fits all his supplies in it:
http://www.amazon.com/gp/product/B00DQFV2NK/ref=pd_lpo_sbs_dp_ss_1?pf_rd_p=1535523722&pf_rd_s=lpo-top-stripe-1&pf_rd_t=201&pf_rd_i=B008CPJ376&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=06S0AV80F43390X9EJ12