CARIBSEA - LIFE ROCK ARCHES 4PK CaribSea Sale! from 11569 /per Qty. Add to Cart This item is currently on backorder but you can still purchase it now and we'll ship as soon as more become available. LifeRock Arch Shapes are the most fantastic LifeRocks yet! A beautiful assortment of 4 arches to make any tank spectacular. Combine with other Life Rock pieces to create amazing aquascapes.