The custom bkr Straw Cap is made for use with the bkr water bottles . It’s made with BPA-free, phthalate-free food-grade polypropylene has a clear silicone valve to hold your straw. To use it you’ll first screw the cap onto the bottle, then insert the straw through the clear silicone valve. This cap is splash resistant. It will keep your water in its place during light turbulence on a flight somewhere fabulous, but if tipped over in your bag some water may spill out. It’s dishwasher safe on the top rack, and the valve is removable so you can wash all the parts thoroughly for zero yuck.