Its a great fit for the bag! I was hoping it would be the tear out block foam.

Hercules Duffel Foam Insert

Fits perfectly

Packs all my gear and more. Very durable, held up at multiple airports, airlines. Held up to my abuse tossing and dragging it around . You get what you pay for.

Love it. Can’t say anything else cause words don’t give it justice.

The foam insert works great. After using an electric knife to make cut I put on a few coats of spray plasti dip to firm up edges. Its great when going to training and staying in a hotel you're not advertising what you have by carrying a separate and obvious “tool” bag.
This bag is great. I use it for a week trip and have room left over. Wheels are stout and roll smooth. The full dimension (LxW) bottom compartment allows for a bulkier item like a coat or get the foam insert and cut out for tools. Another feature I like is the ability to lock every zipper. I just discovered the built in stowable rain/dust cover also. I could realistically pack for a month+, my wife might be able to pack for a three day weekend.

In my opinion this bag would be greatly improved if there were compression straps just for the flip portion of the bag. When you fill this thing up the top portion is pretty unwieldy when you want to access the lower hard case especially since you have to undo the compression straps. Possibly adding interior compression/rention straps would be the best idea since it would also provide some rigidity to the duffle portion. We use this bag as an all inclusive 2 person three gun shoot bag and it holds everything we needed except for the shotguns themselves.