
So the 12mm M6 I needed had a plain top (see screw on the right) so it couldn't be tightened like the left one which I had to buy separately. My guess is that this is what happens when you process millions of screws. It's also not a good thing that the up and down tilt adjustment doesn't use locking nuts, so you'll have to use a screwdriver if you want to adjust the viewing angle (up and down). .

Echo Spot Stand BMK Amazon Adjustable Support 360 Horizontal 40 Vertical Rotation Ball Bearings Bracket Speaker Mount Home Office
19 Review

Wall-Mounted Hanger For Echo Dot 2Nd Gen - Space-Saving Solution For Amazon Alexa Smart Home Speakers With No Messy Wires Or Screws, Perfect For Your Home (Black)
15 Review

Tryone Auto Backseat Tablet Mount Holder For IPad Air Mini, Cell Phone, Galaxy Tab, Kindle Fire HD Switch Lite Or Other 4.7-10.5" Devices - Black
18 Review

Versatile Aluminum Wall Mount Stand For Echo Show 8 2Nd Gen & 1St Gen - Sleek & Adjustable Design Compatible With Echo Show 5 Black
17 Review