JCs Wildlife Exclusive Recycled Poly Lumber Black Birdhouse Predator Guard PROTECTS: Deters or Slows Down Predators from Entering Bird Houses DIMENSION SIZE: 1.5 inch portal hole is the perfect size for Bluebirds and Carolina Wrens EXCLUSIVE: Made exclusively by JCs Wildlife in Southern Indiana GO GREEN: Made from recycled poly lumber which is guaranteed not to crack, peel, or fade UNIVERSAL: Fits over the entrance portal on your existing birdhouse or nesting box