Hydration Pack Hydration Backpack Vest with Water Bladder 2L, Black with Gray | eBay
CAMP Soft Flask
I feel silly for only just realising, but the whole cap from the Salomon soft flasks comes apart allowing you to give them a good clean : r/ultrarunning
SALOMON ADV SKIN 12 SET RED Unisex Running Vest with flasks included | eBay