These grids and connectors are perfect for building your own custom structure for your pet or expanding/replacing parts to a current structure! Please make sure the sizing matches with any current structure grids. The grids measure approximately 13.8"x13.8". They are powder coated NOT vinyl dipped. Powder coating is safer for your pets because it ensures that if chewed, there will be no pieces peeling off for your pet to accidentally ingest. The hole sizes are approximately 1.5 inches so that your adult pet won't be able to squeeze through. We do not recommend putting guinea pigs under 2 months old within these grids due to the possibility of them getting stuck or squeezing through. Do not use these grids to house mice, rats, hamsters or other small pets that can squeeze through a 1.5" hole.