Made For Royal Navy London 5 Minute sand timer Hour Glass 6" The Antique reproduction brass hourglass is 6 inch high and 2.5 inch in diameter. It measures the passage of about 5 minutes. It has two connected vertical glass bulbs allowing a regulated trickle of sand from the top to the bottom. Once the top bulb is empty, it can be inverted to begin timing again. This hourglass is an elegant desk accessory and great for gifting Manufactured & sold by NauticalMart Inc.