Hole design. With a mesh lid, it's easy to drain water when transferring smelt into zip bags, etc. Can be fixed to the edge of a boat with the included clamp. The bottom has holes and is deep, so it has a large surface area in contact with the water, making it easy to maintain the water temperature. There are some minor scratches from use, but it's in relatively clean condition. Includes clamp and fasteners. All photos are included. Height: 37 cm Width: 29 cm Depth: 17 cm Thank you for viewing.