Tail wire loop assembly for cello, by New Harmony Music - these high-quality, precisely engineered, adjustable tail wires replace standard plastic tail loops and allow for clearer projection of sound while decreasing the difficulty of installation. Threaded, with knurled brass nuts on both ends, the loop consists of low-mass, high strength stranded cable. We have tried this in person on several cellos, and must say it improved the sound dramatically! Self-installation is straightforward, and many cellists find this to be an effortless, economical upgrade.