Durable and flexible toy. Put a rock in it and my Lab swims to bottom of pool to get it (not now while it's winter).
Smear a little dog food in it, hide it and watch the fun. Hasn't tore it up yet.

Survived 3 rotties but the mastiff has it now and small bits are beginning to appear around the house. Still makes it one of the best we've ever used.

My lab learned after tearing through her first Horse Ball when she was 1 year old, that the new one was for her to play with, and been with her like two years now. Throw it on the in ground trampoline so it bounces and she’ll get 3ft of air on a run just to head butt it to stop it... Now a nightly ritual... Play!

http://www.amazon.com/Horsemens-Pride-Horsemans-Jolly-Ball/dp/B002HUQMLW

Although this isn't the KONG Extreme Dog Toy, another one of my labs favorites:
http://www.amazon.com/Zogoflex-Hurley-Dog-Toy-Color/dp/B004BRF35K

West-Paw will replace it if your dog chews through it.

This is what our lab loves "Antler Dog Chews"! Gives her something to go after and takes forever to get through. actually if there's 10% gone over the last year that be on the high side. Best thing keeps her occupied inside with no raw hide chew mess which really aren't good for them awayway.
http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Dpets&field-keywords=Antler+Dog+Chew&x=11&y=21

False advertising, it doesn't look at all like an extremely large dog!

Although this isn't the KONG Extreme Dog Toy either, I still need to keep my labs teeth in good shape so I help out by using the Petrodex Enzymatic Toothpaste for Dogs and some nifty Finger toothbrushes I got here:
http://www.drsfostersmith.com/product/prod_display.cfm?c=3307+59+9492+22463&pcatid=22463