These are made by Larsen and are the culmination of quality from all the Larsen level strings: Larsen Regular, Medium, and Soloist. These produce more sound than the Larsen Soloist for the A & D-strings, and more power and volume on the G & C-string than the former "Wire-Core" Larsen G & C-strings. They respond quickly, are flexible, and seem to suppress most wolf tone tendencies on the G & C-strings. The only disadvantage is that they can sound somewhat metallic while playing the open G & C-strings, but this metallic sound tends to disappear on fingered notes.
Larsen level strings: Larsen Regular, Medium, and Soloist are by far the most rewarding strings to play on a cello if the instrument has enough capability to support their tension. Otherwise the result is a muting effect making the extra expense questionable. While each of the versions: Regular, Medium, and Soloist offer a modicum of variation in sound, experience shows that there is not enough difference between them to warrant an exhaustive narrative nor expenditure searching for perfect Larsen version.
These strings are the most powerful of all cello strings for the C & G-String. If the instrument has the power inside and it doesn't sound metallic, this string will bring out its full potential.
With three versions: Forte, Medium, and Dolce, this string dominated the new "non-gut" realm of cello strings for decades. While they are more resonant and responsive than Prim or Red Label, Kaplan, Helicore, Larsen, and Magnacore have shown more tonal complexity.
This is the above average student rental workhorse and well worth the extra cost beyond Red Label strings. There appears to be little or no major tonal difference between the Orchestra or the Medium versions.
The C & G-strings are tungsten and offer power without edge or brightness, which makes them ideal for instruments with too much treble edge in the tonally bass range. The A & D-strings work well with step up instruments and can enhance instruments with more depth that tend to lean toward having a thin treble edge.
The A & D-strings are wonderful for step up instruments and help set them apart from a thin sound normally resulting from instruments having thicker tops and backs.
These strings are the mainstay of public school programs because they just don't break - that is, very often. Their sound is generally metallic and harsh, but their price and long life substantially contribute to their lasting popularity.
For cellists desiring the closest sound to "gut", this is the paragon of all available cello strings. Their success varies with the instrument, but even with the sometimes fuzzy response in upper positions, the similarity to the "gut" sound is often too enticing to resist.