It specifically fits the Milwaukee 48228435 PACKOUT Compact Organiser.The specific tool that this is designed for is model M12FDDX, links are provided here:https://www.milwaukeetool.com.au/power-tools/drills/drill-drivers/M12FDDXKIT202B.html The M12 Install Driver can fit above the swappable heads. The swappable heads have a dedicated storage space in the base of the insert under the tool. Whilst the tool is inserted, it stops the swappable heads from jumping around, even when you use the carry handle. You can now use the belt hook on both sides. There is now WAY MORE room for storage. Meaning you can now easily fit the 5.0ah and 6.0ah M12 batteries. You can also fit the tool with the 2.0ah inserted. There is a HUGE range of custom modular tubs you can print to maximise your use of the front half of the insert. More details below. FULLY CUSTOMISABLE TUBS:Design allows you to have a huge area free at the front of the case for general storage.For that, a massive variety of modular tubs you can pick from for storing extra gear and consumables. There are 18 different tub designs available for you to pick from. You can see more details in the gallery above on photo 3 and 6. Tubs are divided into 3 different versions, "A," "B," and "C." A - The deepest of the tubs extending the full depth/height of the Packout B & C - The B and C tubs work in unison. They are each half the height of the A tubs, meaning they can be stacked on top of each other, doubling the options for small parts/driver bit storage. The B and C tubs may look similar, but have important differences. The biggest being how they interact with the tabs seen in photo 7 above. B - These will actually sit on top of these tabs, in fact you could just use 2 "B" tubs without "c" tubs underneath, and they will still sit exactly flush to the underside of the lid. They also have allowances in their design to allow them to sit flush into the valleys of the clear lid, this stops any gear from jumping over dividers. C - Has cut outs in the walls to allow it to sleeve down past the tabs that B sits on top of. This way they can sit flat on the bottom of the insert, You can use A, B & C tubs all in unison. For instance, you could have an A style full depth tub on the left half of the insert. Then on the right, you could use a B & C style tub in union stacked on top of each other. You have full control over your set up! Simply select with tubs you'd like to print and customise your perfect insert!