The Cichlid Stone 3 Pack is good if you have a smaller tank; need a few extra stones; or just want to get a feel for the stones before you buy a bigger kit for your aquarium. 
It contains 2 medium stones and one small.
Ravine Rock                        5.5" long with a 1.5" opening
ToeHold Rock                     5.75" long with a 1.5" opening
Cichlid Stone, sm round      3.25" long with a 1" opening
 
*made of earth-friendly ceramic
*All hollow and light-weight with a single opening
* all able to turn in all directions so you can decide how you want to stack them.
* won't displace water like ordinary stone
*easy to arrange without worrying about damaging the glass of the tank
*good interior space for exploration, hiding and breeding
*made of earth-friendly ceramic
(more than a quarter of a million Underwater Galleries Cichlid Stones sold over the last 25 years)