I got tired of mine leaking down, so I used a pair of 15x6.00-6 riding mower tubes from Ebay to store my 150. I painted the valve stems red, so I don't forget they're not airworthy.

http://www.ebay.com/itm/SET-OF-2-NE...251776623330?hash=item3a9f0e62e2&vxp=mtr

[Linked Image]

http://g-awaw.org/