A lot of dust collection adapters are long tapered things to maximize smooth air transitions. If your collector/vacuum is sufficiently powerful this may not be as important as having a stronger fitting. This one tries to aim for compact and strong without wasting a lot of material. By moving both hoses into an overlapping configuration and allowing the addition of some stiffening ribs it should yield a durable adapter.
The default sizes here are to go from some old shopvac fittings (~2 ¼" / 58mm) and attach those to a piece of Harbor Freight grey ~4" / 97mm dust hose. If you're like me with a handful of fittings, tools, and hoses then you may find this useful since you can use one model to quickly make STLs to allow you to make everything play nice together.
If you're not super familiar with Fusion 360 yet then here's how you can edit this once you've installed the software (free for hobbyists):
The author marked this model as their own original creation.