2 Sneak Gyros active at the same time
When you activate the sneak gyro and get downed, it makes you invisible and you can revive yourself. After reviving, the sneak gyro is off cooldown and you can activate a second sneak gyro, while the first have 5-10 seconds left.
Every time a sneak gyro dies, the cooldown starts while the another one have over 20 seconds left. This way you can have unlimited stealth.
Tested in PvE and PvP.
Edit: I tested it in WvW and was able to be perma stealted for 1 Hour.
(edited by lokimut.6475)
Out of combat perma stealth is even easier…
You can switch out stealth gyro for another elite a few seconds before it expires, then switch back and throw out another stealth gyro without cd.