How can I pack a second helmet?

[indiana]

I was thinking of bringing both my open and closed face helmets. Is there a good way to attach the one I'm not wearing it to the sled?

 

[muss]

a back pack with a buldge.

 

[indiana]

I'm trying to avoid that.

 

[ezra]

make a choice and commit to it .the less junk you have to strap down the better.