by OSmod » 14 Mar 2011 14:19
Our bags have non-lock zippers by design. Both our central zip (strongest YKK No10 coil) and the non-lock zipper are about getting out of the bag quickly - disorientated upside down and in the dark, you will want to know where the zipper is, and that it will open fast - grabbing and pulling the surrounding fabric is enough.
The central zip is protected by a storm flap, so draft should not be an issue. Perhaps because of the zip's central position, so you generally don't lie on it or have it pressing on your shoulder the potential cold spot/ strip has (to date) never been an issue for us. Maybe we will learn more through this forum as it gets established.
I hope this helps
Clare (OSmod)