CONFAST LDC383 3/8" x 3" Zinc Plated Large Diameter Concrete Screw for Anchoring to Masonry, Brick or Block (25 per Box)

Used 16 of these to anchor our 12x16 Yardestry gazebo to our stamped concrete patio. Didn't have an issue with any of them. Good quality screws when used as designed. As they are NOT rated for outside/wet/damp environments, I will be painting them the same color as the brackets they anchor. If you intend to use ourdoors and don't want to paint them, look into stainless steel instead. A few tips for successful installation: - You MUST drill deeper than the length of the anchor. This seems like common sense but if you're even drilling to the exact length, you will likely reach a hard stop a few millimeters before its tight. Put a piece of duck or painters tape on the bit to show where to stop. - Blow out the drill hole. This is an absolute must do or you won't be able to screw it in very far. All that dust will compact and make it impossible to advance very far. Can of compressed air or even better an air compressor with a blow tool worked great for me. A can wouldn't have been enough for 16 holes. - Use an impact wrench but *CAREFULLY*. This is great for 2 reasons, #1 being you don't get carpal tunnel syndrome after manually screwing over a dozen if these in by hand and more importantly #2 it allows you to get on top of it and put you body weight into it. This helps significantly with getting the threads started and grabbing almost instantly. But be warned that this isn't like using it on metal-to-metal threads, as depending on the concretes make/age you could very quickly strip the hole with too much TQ used too quickly. Slow the impact as you near flush and stop once you get to 1 or 2 impact cycles that slowly turn the screw. - Use the right size drill bit. Seems obvious but just make sure your drilling with the SAME SIZE masonry bit as the screw is. If its even 1 size smaller you won't be able to get it to grab/advance. - Hammer drill. You might be able to pull it off with a regular drill but the hammer drill makes quick work of this and it's what it's designed to do. Your bit will wear faster as it will take longer and warm up/wear down faster because so. If you follow these basic tip, you'll have no issues with these screws. Good product and I prefer them over wedge anchors as it spreads the tension of the achor throughout the whole length of the screw and not just at the end.

Works great

Seams they work really well added epoxy to make sure they stayed

I got these screws to secure my new metal carport down to the concrete driveway it's sitting on. These screws are MUCH better than the blue "Tapcon" junk that shear apart at the slightest tension. These Confast screws also have a much wider thread spacing which leads to less turns to get them in the hole tightly. And with the super-strong concrete I've got, that made the job a lot easier! No wrenched off screw heads with these, and the carport is now firmly attached to the driveway.

Important Tips and why some people give negative reviews or break bolts: 1. Make sure you're using the right size masonry bit. 2. Holes for concrete screws should be at least 1/4-in. deeper than the screw will penetrate to allow a little extra space for dust accumulation. 3. You MUST clean out the hole - I recommend a can of air or a shop vac. 4. If you’re having trouble driving the screw all the way, first make sure the hole is deep enough. If it is and you’re still having trouble, there’s probably too much grit in the hole. Remove the screw and clean out the hole by running the bit in and out a few times. Then blow or vacuum the hole clean again. If it’s still stubborn, back it out and re-drive it a few times. 5. If you still have trouble, install another screw a few inches away. 6. Sometimes you’ll have the opposite problem — the screw will spin without gripping. If this happens, the material you’re trying to fasten to is probably too soft or crumbly. Try a thicker and/or longer screw. 7. If all else fails, you may need a concrete anchor that expands as you tighten the fastener - called a Wedge Anchor. Note: After loosely threading the bolt in, I like to remove the bolt, blow out the hole and then apply a thin layer of construction adhesive (such as Loctite Power Grab) to the bolt threads. Don't over-tighten.

I was very surprised to receive a follow-up message from the seller to make sure that we were satisfied with the product. But since I get material way in advance, the project is due; my review is now months after I purchased it because for me to indicate they came fine and on time is not the review that you are looking for. I must say that this product is recommended for someone in the trade because you do need the proper equipment, and they also need some specific techniques that I will not repeat because a couple of people have already made a great list of things to consider. The one extra step I added was to "wet" the anchor threats with silicone to sort of "glue" it in place and perhaps minimize movement from ground expansion. I felt very supported by the seller by following up with me (which perhaps shows my effort in writing a review that I seldom do), and to reassure you that these are quality materials, just make sure that you do have the appropriate tools and follow proper procedure.

These were great and less expensive that name brands. Does the job well.

super strong connection - works really well and holds very secure.

I found that the 5/16 masonry bit that matches these screws does tend to deflect sightly making the screw difficult or even impossible to drive in. Over a shorter hole there is far less deflection and the screws hold very well. The 2 ½ inch screw however frequently seizes part way in.

Es un producto excelente, cumplió al 100 mis expectativas

Used the whole box the first day! Strong and easy to use. Will be buying more

I was prepared to be disappointed compared to the usual top tier brand I get. Pleasantly surprised. Awesome fastener.

used to tanker my 12ft x12ft door opening they seem to hold very well in concrete hope they work as good in brick and block