A "danbuoy" is a generic term for a floating rigid pole with a flag on top. "Jonbuoy" is the trademark of an inflatable rescue device, which combines some of the features of a lifebuoy and a danbuoy. Confusingly, Jonbuoy also make an inflatable danbuoy.
2 very intersting pics of the chappie sitting in the Jonbuoy, with one at £849.95 just because it has a 'head mounted'? I think I would rather go for the one without the head at £58.16. Save some £800 and just 'go' in the sea if I need to go until I'm rescued!
My favourite out-take was a scene in the Waltons where John-boy asked...."What shall I do with the chocolate Santa Claus?" and the answer was..."Hang him up by the balls on the Christmas tree".... never made it into the episode of course... Shame!