M2 x 0.4mm x 2D Helicoil Wire Inner Thread Inserts, Coiled Wire Helical Screws, 304 Stainless Steel, Metric, 60Pcs

Sold as 1.5D, but only has 7 full threads. With a 1.5mm pitch that puts it at 10.5mm in length, which is just barely over the 10mm expected of a 1D thread insert. They work otherwise, but I didn't specifically pick a 1.5D thread insert just for giggles, I needed those extra 3 threads. The product specs and images are a lie, so whether or not it's intentional that earns it an instant 1 star. (In the image it shows even smaller than 10.5mm in length, but the threads are stretched a bit during installation)

We use these for our laser cut acrylic projects for when we need screws in to the plastic. These always work

Good product.

These worked very nicely to add machine thread holes to fiberglass on my boat. I was tired of repairing holes where wood screws directly into fiberglass stripped out or left stress cracks. This also works better than a wood screw in thicker fiberglass where wood screws tend to bind and snap off. The other benefit is that wood screw threads cutting into gelcoat tend to create stress points that start stress cracks in the gelcoat that radiate out from the screws. Using a helicoil with a machine thread screw seems to eliminate that problem. It is important to use an anticorrosion compound like Tef-Gel in the marine environment since, while these helicoils are stainless steel, they are not a marine-grade alloy.

Works great!