Wensilon(20 pcs) 1/4"-20 Premium Zinc Plated Carbon Steel Drop in Anchors Assortment, Knurled Drop-in-Anchor for Solid Concrete, Internal Forced Expansion Screw Bolts

Good quality as I used this to install an outside gate (it's a cheap plastic gate so I wanted to keep the option of changing it out in the future so this allows me to unscrew the bolt without drilling more holes later). You'll need to buy a drop-in anchor tool to get it to work properly; it will likely break or not work if you use a nail and screw to hammer it. This does not have a "lip" to catch the edge of your hole, so you will need to be careful how deep you drill your hole through masonry (some of the more costly versions has a lip).

They say to use a 3/8 bit to drill the pilot hole for the 1/4-20 anchor. Because of the aggregate in the concrete the bit can jump a little bit and the hole ends up too big. I used a 5/16 bit for the pilot hole and it was nice and snug. You'll have to tap it in before you set it, but the result is a perfect fit.

If you use a 3/8 drill the hole is so big the anchor spins when you try to tighten it, 5/16 works fine, you need to tap it in with a hammer. It was just dumb luck I bought a set of drills instead of just the 3/8 I supposedly needed, I would have been perturbed if I didn't have the right drill.

The title for these is inaccurate, this isn't an assortment, but I wasn't hoping to get one. I wanted all the same size and that's what I got in a heavy plastic bag. These work well and are the way to go when working with larger holes in cement or concrete. Drill the right size hole and insert them, sometimes requiring a little light tapping. When you screw your bolt in, it expands the knurled section because that end is slightly wider/thicker than the other end. The more you tighten it, the stronger it holds. Simple operation, but the best way to secure heavy objects.

These are great; they are stainless steel which I would never use anything else to mount outside in the concrete. The listing needs to be corrected, these are not an assortment, and they’re all one size which is fine. I’m sure that got lost in the translation, but it was easy enough to tell what they were. I've used this type of concrete mount to bolt things down and they look like they will hold up very well even in a high wind.

I tried it in a sample paver block. Identical to my paver blocks. Tried it 3 separate times in 3 separate locations. These pavers are a decent size too!! Never locked into place, always loose. Like I said trash.

These must be 'set' by tapping the center but no tool is included. I used a center punch.The 1/4-20 bolt does not screw in very far so you must use a short bolt and weigh the end result for strength.

I have a brick house, and its difficult to drill into the brick, so quite often I drill into the mortar between the bricks, and use a plastic drop anchor. But its really hit or miss as to whether it holds in, and worse, over time the plastic collapses and it gets even looser. These metal anchors really hold. Especially if you install the anchors so when the inner section spreads open, they spread open in the direction of the brick itself. For some cases, like ceramic tiles, stick with plastic, as these could spread and crack the tile. But for pretty much every other anchor application, these are far superior.