Is this the world's lightest day-sac, plus lots more lightness from Sea To Summit. 
 
Just a quick heads-up on a couple of neat lightweight bags from a brand we've not come across before called Sea to Summit - the co-founder of the company was Tim Macartney-Snape, the first person to make a continuous journey on foot from sea level to the summit of Everest.

Anyway, the brand makes some really nice lightweight outdoor equipment including incredibly light dry bags made from Ultra-Sil, a Siliconised Cordura fabric with a PU coating for complete waterproofing and a roll-top closure.

The bags are available in seven sizes from 1 litre to 35 litres and weigh between 20 and 65 grammes and yes, you did read that correctly. The 8-litre bag pictured weighs a mere 30 grammes and retails for ￡8.99. Ideal for keeping things light and dry at the same time.

Also made from the same Ultra-Sil fabric is an Ultra-Sil pack liner and our favourite thing, this bonkers light fold-away 20-litre day sac which weighs a ridiculous 68 grammes and packs down into a package so small you could just about carry it on your key ring. Retail price is ￡17.99, ideal as a travel day pack or for emergency shopping or, at a push, a mega-lightweight summit pack.

Lots more besides including our favourite name of the week, the iPood! a lightweight trowel for outdoor use. Isn't there an app for that? No, we're not making it up.

And that's just scratching the surface, there's also a whole range of sleeping bag liners and a neat all-in-one Wilderness Wash that's an ultra-concentrated cleaner you can use as a body wash, shampoo, dish detergent and to wash clothes.