I bought an Equinox Bivy Bag a long time ago and have never used it. Unfortunately it had a right hand zip whereas all my sleeping bags bar one have a left hand zip.
I asked Marco at As Tucas to retro fit a left hand zip. For €30, he obliged. This only added 9g to the bivy, bringing the weight up to 195g (without the mesh sack).
I’ll give it a whirl as a bivy bag, but I think it will also be very useful as a sleeping bag cover to add some extra warmth and damp protection in cooler months.
Marco is always willing to look at modifying existing gear, so if something is not quite right, it’s well worth asking him. He is also considering whether to offer similar bivy bag at some stage.
Disclosure: I paid As Tucas for this modification. I have no formal or financial relationship with As Tucas.