As above really. Ideally around 25l, pockets on the outside for lock/lights, and I prefer a lid with buckles to a zip. Not that bothered about the freeflow-type back.

I’ve had panniers before and might well end up going back to them but just wondering what good backpacks are around and worth a look. Had a messenger bag for several years but beginning to feel like it’s not doing my back any good.

I have a alpkit gourdon 20 litre. Great for commuting but the 25 litre version does not have external pockets.

I adore my montane cobra 25 super comfy and light

I have a deuter race (20L I think) and it’s great, if just a little on the small side as it’s full with a change of clothes so you can’t get food shopping on the way home

I like my OMM race light, but mainly for he hip pockets for keys / wallet / phone.

I’ve been impressed with my Osprey momentum 26. Lots of well designed features and comfy to wear when fully loaded.

edit – opens with a zip though…

I’ve been using an Overboard pack for last 2 commuting years. Really rate it..
Waterproof Backpacks