Made from Silicone coated PU ripstop nylon this groundsheet is strong and durable. It has a hydrostatic head rating of 3000mm.
Gram-counter Gear says:
There are 3 sizes available: Small - 'Organiser groundsheet' for sitting outside the tent. Medium - Groundsheet that one person can sleep on. Large - Two person groundsheets.
A footprint protects the groundsheet of your tent from damage. I would only usually consider one if I knew I was going to be camping on stony pitches.