The large black operational travel bag, often known as a ‘grip’ is issued to modern service personnel to fulfil the same role as the kit bags of old. It is a large and practical way of carrying spare uniform and equipment from one deployment to another. It is basically a large black holdall:

Like any civilian holdall it has a pair of carrying handles on the top to allow it to be picked up:

What makes it a little unusual is that under two flaps on the top are a pair of shoulder straps that can be pulled out to allow the bag to be worn rucksack style:

in addition to this, at either end is a heavy duty grab handle to allow it to be moved easily:

Note also that there is a pocket at both ends of the bag. The bag will often carry heavy items, so is reinforced by bands of nylon webbing sewn around and under the main body of the bag:

Note also the six rubber pads on the base to help reinforce the base and lift it up slightly if it is dragged along the ground.
The label is sewn into the inside of the bag and as well as the NSN number has space to add the owner’s name and service number:

This black holdall is a very popular piece of kit amongst servicemen and women:
They are, unbelievably, a very good piece of kit. Far better than the deployment issue black rucksack which, after first impressions, is actually rather sh1te.
Whilst another user explains:
The large black bags are the mutts nuts, hold more than you’d think and are very robust.
Not all agreed however as there seems to have been some issues with the strength of early production examples:
They’re a good design but the build quality isn’t very good. I’ve gone through two of them now-broken straps, zips snapping-all down to poor quality. However, I’ve got two different ones now and they both seem to be of better build quality so maybe it was just an issue with the earlier ones.