I've loved gut strings for a long time. The Oliv D has a wonderful sound with warm characteristics throughout. At first, it may start a bit raw, as it will need time to develop and "season" properly. Tuning wise, it stabilizes after just a day or so. As one plays on it, it will start adapting to one's playing style and sound production. This string has three different gauges. But even the thinnest gauge is much thicker than steel D strings. If you want to try gut strings you have to modify your bridge to fit them properly (as well as the nut) by widening the string grooves. To play on gut requires a full commitment because they're not for everyone. Also, not every cello takes to them. I use steel A and Olivs D, G, and C. My old French cello has never sounded better!