Review on Glarks 200Pcs Wire Insert Screws Sleeve Assortment Kit - Premium 304 Stainless Steel Metric M3 M4 M5 M6 M8 M10 M12 Helical Thread Coiled Sleeve for Automotive Repairs by Leo Puente

Not sure if the manufacturer is asking for "transparency" but the spools are well made and a very tough material. I have used them to repair same diameter inch threads and found them difficult to install due to the tighter thread pitch on the spiral spool. It was the positioning tab that became my sore point as the tough material would easily come loose and I had to twist the remaining neck to get enough grip to finish my rethreading. I find the material to be of high quality and keep a set ready to drill new metric holes.