CHEW GRENADE, Beef Flavored, Medium 4-1/4" by Phydeaux Ent. / Bite-A-Bone Products [phy-i2] SERGEANT SPIKE'S CHEW GRENADE, Beef Flavored, Medium 4-1/4", SuperFlex Material for Medium sized Dogs. Extra strong and thick to hold. Hole in center for treats or peanut butter. Lots of bumps and ridges for extra fun chewing. Price: $9.56