Try a search on your question and you should come up with a lot of good answers....
You need the following minimum:
Beacon, Shovel, Saw, Probe.
Do a search on the items above and buy the best you can afford.
Do not ride in Avalanche risk areas with anyone who does not have the above items...
I will follow up with Jet Craft, but...
Has anyone had an extension built for their 6.5 foot JET CRAFT sled deck with side slides?
Can I see pictures of your deck with the extension? (It doesn't matter if it is Marathon or whatever)
Thanks,
Indy.