Expandet nylon anchors are expensive so I only use them when I'm drilling a hole the cheaper anchor won't catch (spins in place ) or when the screw I want to use doesn't exactly fit a cheap anchor. The shape of the dowel prevents twisting in the drill hole. Anchors are supplied in 4 cubes of 25. Each cube is held together with two-hole plastic tape to make it easier to locate the correct size drill bit and screw (see images). These anchors can also be easily cut to the desired length. The white Expandet anchors are marked for 5mm or 3/16" holes and screw sizes 4-5-6 (3mm to 3.5mm). These anchors are made in Denmark. Because of the price I only give the product 4 stars.