Kong

[loot]

I use the Indian rubber balls.which are lacrosse balls. Had no problem. Never unattended.

[Eliman]

I give my hounds the toughest Kong ball they make i believe it is called super Kong it is black but they will still chew it up if left with it to long play it safe keep an eye on them with it I usually give it to them for 20 min every other day during a keep

[Nut]

Some just don't like it. If you put something in they just lick it out lol.