shop vac adapter
Works great I was able to make an adapter to connect a smaller diameter hose to my larger diameter shop vacuum hose connection.

It seems to work, but a little awkward
I am using this to attach my Bosch orbital sander to my shop vac. The adapter does work. Unfortunetly, it is made of a flexible material, and tends to slowly slip off. I have used duct tape to hold it on, but that only works so long. Next up I will get a hose clamp. I wish it were hard plastic and fit over the square to round adapter on the sander.

TOOL ADAPTOR
THIS IS THE BEST, AND PROBABLY THE ONLY TOOL ADAPTOR OUT THERE. I HAVE A SHOP VAC THAT HAS 2 DIFFERENT SIZED HOSES THAT DID NOT FIT THE EXHAUST ON MY SANDER, THE COMPANY DID NOT MAKE AN ADAPTOR TO REMEDY THIS PROBLEM, SO I FOUND THE ADAPTOR AT MY LOCAL HARDWARE STORE, CUT IT TO FIT THE SANDER, AND PLACED IT ON MY SHOP VAC HOSE. THE HOSE NOW STAYS ON THE SANDER FOR ALL DIFFERENT TYPES/HEIGHTS OF SANDING. THIS TOOL SOLVED A MAJOR PROBLEM OF KEEPING THE DUST IN MY WORK AREA DOWN. THIS ADAPTOR IS A MUST FOR EVERY OWNER OF A SANDER, ROUTER, PLANER, OR ANY OTHER PORTABLE POWER TOOL THAT GENERATES SOME TYPE OF DUST.

You won't get hosed on this one
I have used a couple of these devices to connect the dust port on tools to vacume hose. Funny how there are standard sizes of dust collection and vacume hoses, but every tool seems to have a dust collection port that is in some odd size. Nothing fits. This adaptor gets in between the odd sizes of tools and standard size of hose. You can easily trim this adaptor to fit either an inside diameter or outside diameter of the adaptor. Like I have said before, it does what it says it will do.