Product review (4 stars): Male to Male Fittings
This is a slick product. We've had trouble with the hose sliding off the vent pipe, so this is a great idea. A couple warnings though:
1) The plastic connectors are both male fittings. If the pipe in your wall is also a male fitting, the plastic coupler will not slide into it, even after you prepared it as in the instructions. And once you've cut it as instructed, it is compromised--and inside the wall. I straightened out the tabs I cut in the pipe and used aluminum duct tape to attach the platic fitting to the pipe in the wall. I'm hoping the adhesive on the tape will hold up under the heat. Otherwise I will need to cut a larger hole in the wall to replace the elbow that I damaged preparing it for the DryerDock fitting.
2) You rotate the two pieces together to attach. There's not a lot of friction holding them in place (they don't truely "lock"). If there's much spring force to twist them back counter-clockwise, they will come apart. I'm planning to drill a hole through the two to insert a pin & thus lock them in place.

Docking (no pun intended) one star because the instructions could have warned about pipe fitting incompatibilities & the locking mechanism could be better.

All that being said, I'm planning on buying a second DryerDock to put on the dryer side of the hose, as the hose tends to slide off there too. The dryer side connector also looks to be male, so I'm going to check at a hardware store for a short slip fitting to join the two male ends.