Yes have been using one for years its my zip of day pack with the yoke as well so carries
58 water bottle
crusader cup and cooker with green heat sachets
days worth of brew kit ( Kenco 3 in 1 coffee)
couple of boil in the bag rat main meals
pocket binoculars
KFS
Pens, pencils, markers, note book
Mora Clipper ( might change this out with a EDC legal folder)
Sewing kit
small 1st aid kit + paracetamol etc
Ferro rod
couple of mini back up torches
plus room for a little more depending why im off out ie ID books
as i said it then zips on to my bergan for longer trips but teh kit is the same the other side i use a std military side pouch for Hammock and Hobo billy set and my Carving axe and large folding saw tuck nicly beteen the pouches and the main sac
ATB
Duncan