Last year, I purchased a Montbell Aqua Gripper Sandals (size S) for water play. The size is listed as 23.5-24.5cm. These are unused, only tried on at home. They don't quite fit, and I no longer have opportunities for water play, so I've kept them stored. Please refrain from purchasing if you are concerned about home storage by a private individual. I hope to pass them on to someone who can use them. Below is information from the official website: --- These sandals are perfect for water play, using Aqua Gripper, which provides amazing grip on underwater rocks. You can put the thong between your big and index toes, and adjust the fit with the Velcro strap on the instep. The straps provide a high level of hold, making them difficult to come off in the water, perfect for water activities. Specifications 【Material】Body: EVA foam / Outsole: Aqua Gripper 【Weight】250g (size M, one foot)