This is a crevice tool for a Shark Navigator Professional Lift Away vacuum cleaner. I made this in Onshape. Feel free to adapt this in any way you see fit.

4TH ITERATION
I'm sorry. I just really like fillets.

3RD ITERATION
Why do I keep making these things? Okay, well, this one was necessary, but I'm done. Okay? I'm done. No more after this one.

I had to flip the catch around, it was angled backwards in Mk.2. And I was still having to sand the final just a bit so I added a little bit more tolerance. And I defined the size and position of the rectangular end relative to the attachment. I just eyeballed it in previous revisions. I thought that wasn't the best way to do it.

2ND ITERATION
I've added additional clearance to make for a better fit with less post work and I added features to improve airflow and reduce turbulence inside the tool near the attachment point. This will result in a probably immeasurably small improvement in suction thanks to less loss of energy to turbulence and less dirt buildup inside the tool.

https://cad.onshape.com/documents/c0098c74fabf15220efffcbb/w/ab17b34ab6d89a53e4131dc7/e/ac5487adc4c36c86f423cd54