I'm kinda mad....but only so mad as $13 worth of useless product can make you!
When I bought my Vacmaster VWM510 vacuum on Amazon they listed on the same page a micro-cleaning kit V1MK as being a frequently purchased item with the vacuum. Little did I know that the Vacmaster (which I love by the way) uses a non-traditional 1 7/8" hose, whilst the micro-cleaning kit fits a 1 1/2" hose!
Now why in the hell would Amazon list it like that, if they were incompatible?
Amazon.com: Vacmaster V1MK Micro Cleaning Kit: Home Improvement