SILVER 31.5 MM RO CAPS Even when the product or liquid is shaken upside down, these caps and closures provide a perfect, leak-proof seal. These closures are the best option for protecting your items against spills, moisture, and air. These closures also provide customising options, which increases a product's perceived value. These closures work well with the lead- and toxin-free glass containers we provide. The attractiveness of our FSSC 22000-certified and food-grade glass bottles is increased by these stunning coloured closures.