LeadTurn_SD
Contributor
My recommendation would be to get a "real" regulator, rated for cold water, to use as your backup or "octo". Same-brand as your primary is usually a good idea to make servicing simpler, but is not a 100% requirement. Simple and rugged is "ok", it need not be adjustable, but needs to be able to perform in cold water with high air flow (think a stressed diver breathing at an elevated rate), and needs to deliver high air flow without freezing-up.
To turn this discussion in a different direction: Consider donating the regulator you are breathing from (your primary) to the OOA diver. Now, what quality secondary (octo) would you purchase, if you had to breath from it in an emergency in cold, deep water?
Just something to think about. You don't have to break the bank to get a decent octo, but don't get something too cheap either.
Safe Diving!
To turn this discussion in a different direction: Consider donating the regulator you are breathing from (your primary) to the OOA diver. Now, what quality secondary (octo) would you purchase, if you had to breath from it in an emergency in cold, deep water?
Just something to think about. You don't have to break the bank to get a decent octo, but don't get something too cheap either.
Safe Diving!