214912-010 4/0 Gauge Fusion® Solder Thimble (10 Pack) - This patented 100% copper alloy thimble is tin plated for corrosion resistance, and it is preloaded with flux and solder in barrel so all you have to do to install it is insert the cable and add heat. You get a perfect solder connection every time, fast, and convenient. Available in wire gauges 2 to 4/0, they also fit all brands of cones. The wire gauge is printed on barrel to help ensure that you get the size appropriate for the cable you are using.Ready to use, "Just add Heat".