Really thrilled with these bags and, although Lakeland recommend the clips for them, I find they don't need to be sealed as that can sometimes form condensation. I merely fold the top of the bag over and pop it in the chiller box. All my fruit and veg are immediately stored in these bags and there is no doubt whatsoever, the food stays fresh and delicious for many days longer, sometimes a couple of weeks! I seldom have the need to discard any perishable food since using these bags and recommend them to everyone. Well done, yet again, Lakeland.