This is a flip-up sports bottle cap designed to be used by replacing the cap of a plastic bottle. It's recommended as an item that helps you hydrate easily and efficiently without the risk of losing the cap. As shown in the first photo, there are five colors: white, red, blue, green, and yellow. This listing is for a set of 5, one of each color. ★Important Notes★ ・We cannot create a 5-piece set with a combination of colors like "white x2 + blue x2 + yellow x1". (If you have a preferred combination or quantity, we may be able to accommodate you with a dedicated listing depending on stock availability, so please consult us in the comments.) ・All items are unused. Please detach the closure of the opening before use. Also, we strongly recommend washing the product with dish soap before use. ・This product is basically installed after removing the ring (part of the cap) that remains on the plastic bottle body when you open the original cap, as shown in photos 2-4. If you don't remove it, it may interfere with the installation and prevent you from tightening the screw, which could cause leakage. In that case, please remove the ring on the bottom side of the product as shown in photo 5 (you can pry it off with pliers, etc.). ・This product fits the standard plastic bottle mouth size (diameter: approx. 28mm). Please note that it cannot be attached to bottles with different diameters, or even if the diameter is correct, bottles with incompatible screw threads (although the seller has never encountered this). We do not accept returns for any reason from a hygiene perspective. Please understand and purchase accordingly. #WaterBottle #WaterBottle #Nalgene #Nalgene #Flask #Hydration #Mountaineering #Hiking #Walking #Cycling #StrollGoods #Pet #HeatstrokePrevention #Ultralight #UL #SmartWater #LIFEWTR #SmartWater #LIFEWTR