I love Screek mmwave products for Home Assistant. I’ve had them for about 18months, I’ve purchased 12 in all, and have replaced 6 of my PiR Zigbee sensors with SCreek, first the 1U, I have a couple of 2M’s I think, and about 6 F2s. I love the F2’s. It’s an all around capable performer, instantaneous for motion and very sensitive for presence. And quite configurable without needing the HKLRadar app that the earlier sensors needed. The 3 zones with sensitivity settings that seem to work have made it my go-to. Nothing wrong with PiR, but the fewer batteries I have to change, the better.
But sometimes these sensors are TOO sensitive, as the mmwave radar not only goes through drywall easily, but goes backwards through drywall. I wish that wasn’t the case. I was installing a new F2 today, and it was just too sensitive, if I notched it down too much it didn’t work reliably for the intended purpose. But increase the distance and sensitivity (BTW, higher numbers mean less sensitive in the Home Assistant software) and the bathroom light was coming on when walking in the hall.
So I went to Home Depot and walked the aisles. I settled on an 8 foot length (there was nothing smaller) of vertical steel stud, about $9. Out came the Dreml, one of my favourite tools. I cut it to size, painted it, mated the 2 pieces with silicone and installed it. Perfect operation. And I have enough steel channel for 20 more sensors. 
Pictures attached. I think it’s a 1U in the picture, I did a second one that was also over-sensitive after great success on the F2. It’s really a no-brainer.
