Mustang PFD

Does anyone besides Mustang make an HIT style inflatable that will only inflate when submerged?
I have the Mustang MIT that will and does inflate when it decides to!
I am unable to determine if Onyx or others make a HIT type.
I find the Mustang elite 28K (has back)for around 150 and the md 3183 02 (open back) for around 200.
Any suggestions appreciated.

I have had both Onyx and mustang HIT PFD. The only one that inflated was one that got wet and was left in a compartment that was hot and damp. All the rest have been just fine even in the rain or spray, as long as I hang them to dry (usually on my Rod holders) after a day fishing.