The 15 liter zip on has been beefed up .
The 15 liter has a two clamshell zip compartments that completely open up - a shovel and probe pocket in front , with the main compartment in back .
The 15 liter zip on has been beefed up and has a two clamshell zip compartments that completely open up - a shovel and probe pocket in front , with the main compartment in back .