This item was created by me using a 3D printer and handcrafting. It has been used successfully in actual fishing. The main body of the plastic (PLA) is 3D printed, while the stainless steel eye and the spring for opening and closing the cage are handmade. Images 1-3: The cage is designed to open simultaneously upon water entry. It's designed to open as easily as possible within a range that doesn't interfere with fishing, so you don't waste time with the cage not opening. Also, the spring is designed not to bounce up excessively to prevent the leader from tangling. See images 4-5: There is a screw-on lid on the bottom cage, allowing you to insert a weight of your choice. Weights of a certain size can be inserted directly. I use a size 12 nasu-gata (eggplant-shaped) weight. Weights that don't fit can be shaped with a hammer without melting them. The weight of the item itself is approximately 57-58g. See images 6-7: The concept is large capacity, and it feels like it holds more than twice the amount of chum as a commercially available Apollo Ippatsu Kago (one-shot cage). The diameter is also large, about 5cm, making it very easy to put in chum. You can attract fish by scattering chum all at once with fewer casts. It's also perfect for live bait fishing. See images 8-9: During a single test fishing trip (about 3 hours), I caught two 45cm sea bream! ヾ(*´∀`*)ノ Please understand that this is handmade, so there may be individual differences. This is a set of two handmade Ippatsu Kago (one-shot cages). The weights and Apollo Ippatsu Kago shown in images 5-7 are not included.